If you want to tick off your suitemate, consider an endless recording of "It's a Small World". People have been known to hurl themselves in front of buses because of that one...
However, to expand your classical library, you've already got a good start. You know some classical pieces that you like, so start expanding from there. Other works by that composer, other groups performing that work, other performances by that group... it expands from there.
Happily, expanding your classical collection is one of the cheapest things you can do. For some reason, the CDs are a whole lote cheaper
I don't know if you can do the same thing in Merry Old, but here you can go into music stores and listen to the CDs before you buy them. That will help you weed out a poor performance, if you're lucky. And you can also ask at the store for input on other classical music selections. *Someone* at the store will probably be into classical... somewhere...
Good luck! Expanding your musical horizons is always fun!