5 must have classical recordings

Rachmaninoff plays Rachmaninoff - concerti !!! He makes all other great pianists sound like children... It's simply a great Russian poetry...

Rubinstein plays Chopin

Romantic music of Spain - Janos Starker (cellist)

Heifets ( any recording )

Maria Callas ( mad scenes )

Thrift store vinyl is a good gateway into classical music. You can often get great stuff for practically nothing. If you don't have a turntable, it's a good excuse to get one. Classical sounds better on vinyl anyway IMO.

Issac Stern's recording of Mendelssohn's Concerto in E Minor for Violin and Orchestra and Beethoven's Two Romances with the Boston Symphony (conducted by Seiji Ozawa) is one of my favorites that I discovered that way.

I'm sure you'll get plenty of "serious" recommendations from this thread, but Wendy (formerly Walter) Carlos' Switched on Bach (Bach performed on Moog synthesizers) is great fun.

Jordi Savall performing Orlando Gibbon's "Fantasias for Viols"

Its tough getting into classical because of the bewildering number on Composers, compositions, and interpretations. One way to get started is to do some internet listening to a good station. There are many, but my favorite is WCLV. I tend to point people to recordings of music that I consider to be close to flawless in both interpretation and recording quality. Here goes with my top five list.

1.Schubert Rosemunde Quartet by the Belcea Quartet on EMI. My favorite classical recording, bar none. The Belcea is vastly underrated.
2.Hilary Hahn Brahms violin concerto on Sony. Paired with the Stravinski. Both just great performances of great music, and quite nice recording quality.
3. Stravinski, The Rite of Spring on Deutche Grammophone. Salonen and the LA Philharmonic
4. Beethoven 9th symphony, on Bis by Osmo Vanska. If you don't love this there is not much hope.
5. Dvorak Cello concerto by Queyras on Harmonia Mundi. A wonderful recording and performance of the best cello concerto ever written. Enjoy.

I would suggest the following :
1. Handel water Musick Harmonia Mundi HMU 7010
2. Corroboree , Antil , OASD 7603, my favourite
3. Ein Straussfest , Erich Kunzel Telarc DG 10098
4. Le Cid, Massenet, HMV Greensleeve, ESD 7040 - cheap and good. value for money
5. The Planets, Holst, Zubin Mehta, CS 6734, cheap and good

and many more