What would you recommend as some easy transition music for someone who finds late era Beethoven "a bit modern" but is trying to branch out a bit with a view to eventually listening to more 20th & 21st century. I don't want to go straight into something that is going to turn my head upside down, something with some discernible and familiar patterns, form, etc. but outside my usual comfort zone of Bach, Haydn, Tartini, Hoffmeister, et al. I don't like listening to piano music or jazz, but otherwise I'm open to all possibilities. Convert me!

I share your wariness of overly modern music There is stuff that's approachable and not necessarily wholly atonal. Modern choral music for example by composers such as Lauridsen (e.g. Lux Aeterna) or Whitacre. I like works like Langlais Messe Solennelle which is spikey but something you can get on with (his organ music is good too).

Maybe start off with neoclassical, if you're looking for a sense of structural familiarity. Try Dumbarton Oaks, by Stravinsky, which is something of a 20th-century Brandenburg Concerto.

Staying British might also keep you in more familiar territory: try Britten's violin concerto or his string quartets.

Following on to the neoclassical idea -

Prokofiev - Classical Symphony
Stravinsky - Pulcinella

I find the Firebird and Petrouchka (also by Stravinsky) very listenable; I think they have an abundance of nice melody. Rite of Spring less so if unfamiliar with modern music.

Yuk! I can just about tolerate Pulcinella...

Not all neoclassical music is alike, and everyone's preference comes to the fore just as with any other genre. I don't like Haydn's 'humour', and I don't like that of Prokofiev 1. On the other hand, Stravinsky's Symphony In C, his 'war symphony', is still neoclassical and highly recommended listening, but it is also absolutely brutal in its impact.

Rachmaninoff- The Isle of the Dead. It has your discernible form/motifs, all main/counter melodies are based on Dies Irae so there's a link with older music. Despite this it is very much Romantic and a beautiful piece. A good stepping stone.

Ravel is probably your best bet out of the French. Bolero, La Valse and Le Tombeau de Couperin (the orchestrated version not the original piano suite).

An obvious English suggestion would be The Planets (Holst). I've never studied it/seen the score but there are elements that run through all 7 movements, yet they are so different that it never becomes repetitive. Definitely worth listening to.

Those are all I can think of at the moment. The American composers that don't come under Jazz (e.g. Ives, Reich, Cage, Glass) would probably be a little extreme. I don't like the Second Viennese School myself so wouldn't recommend them.

When you say "piano music" does that include piano concertos? How about piano accompaniment? If you teach violin, have you come across the Szymanowski Mythes? The outer movements may be a bit heavy, but the middle (Narcisse) is worth a listen.

Of course it isn't all alike, and of course it'll be subject to preference. I suggested them because they have familiar form, and are tonal. That doesn't mean they'll be automatic favourites. RoseRodent might well hate everything that everybody has suggested here!

Thanks, yes that's exactly what I was getting at. I'm trying to find something which is a bit new and different but where I'm not totally lost, like the traveller who takes a holiday in another developed European country and finds the language, culture and food broadly familiar but a little exotic and different. As opposed to the traveller who is taken to rural China and finds he cannot even guess at how to read any of the signs around him and the food is all duck tongues, insects and toad. I'm venuturing into baguette and camembert territory at the moment, not quite green ant soup.

As it happens, the local music shop sale had a copy of Spectrum for violin on sale so I decided to buy it to see if I could get my head around any of them, and I actually (shock horror!) like some of them!

The Spectrum books are interesting. Not being a string player I'm not familiar with the violin one(s). But I'm using some of the piano books, and I always make sure that students are aware of a good sample of the contents before I suggest they invest in a copy! Careful to include the 'here are seven note clusters - play them in any order you like with the sustaining pedal depressed and eat an apple / sharpen a pencil / close and open the lid between repeats ' type of piece.

Northen Lights (which is on the grade 3 list for 11-12) is proving popular with quite a few of mine. Two are cautiously exploring September Chorale and Red Bird. There are some that I probably would not enjoy teaching - but quite a few that I do like.

I think the Spectrum books are excellent, giving a taste of so many different compositional voices in each book. I was at the launch event for Book 1, where all but one of the composers were present. I think it was Michael Finnissy who said he thought the book would make a brilliant textbook for young composers because they would meet such a variety of ideas expressed in individual ways. It wasn't long before Book 2 appeared, with even more different composers writing pieces with fewer technical demands. I met Thalia Myers who was responsible for commissioning the composers (full marks to ABRSM for taking on the publication). Her major requirement was that they should write within certain technical limitations but without compromising their unique musical language, and some composers turned down the commission to write at the simpler technical level because that was too difficult. All the composers in books 1 and 2 were British, but in book 3 I think every composer was from a different country.

Just suggestions: if you can cope with Berlioz' Symphonie Fantastique try:

Debussy: La Mer, L'Apres midi d'un Faun, Iberia. (You may find Jeux mentioned. A pleasant piece but Debussy at his most extreme.)

Ravel: Daphnis and Chloe; and his Piano Concerto in D (for the Left Hand)

Schoenberg: Verklaerte Nacht/Transfigured Night. Was originally written as a string sextet but later arranged for String Orchestra.

Holst's Planets Suite is popular and very good. See if you can find the Previn/LSO recording.

As others have suggested, Stravinsky. Le Sacre du Printemps has been mentioned. Some listeners have
difficulty with it - Stravinsky relies heavily on dissonance but the work is basically modal and highly rhythmic - irregular rhythm. Much depends on the recording you listen to. Stravinsky's own isn't so great.
If you can acquire a DVD of the ballet 'Firebird' the music makes more sense than as just a concert work to me.

Bartok: Music for Strings, Percussion and Celesta

These will bring you into the first half of the 20th century. Then there are a few English composers: Vaughan Williams, Bax, Elgar. Elgar's Enigma Variations is easy to get on with. George Butterworth's A Shropshire Lad is rather beautiful, definitely worth a listen.

These are within reach of tonality / modality. For atonal works, try Schoenberg's 5 pieces for Orchestra Op15, and perhaps Hunphrey Searle: Symphony No.1

Hope this helps.

Berg's Violin Concerto is worth a try, too. Serialism which has just about secured a place within 'mainstream' concert programming.