I have a horribly sounding e-piano that I would like to hook up to my pc to play with various synths. It wouldn't hurt if it has some usable sounds on board since I don't know any good piano 'synths' for linux.
I would also like to use it with rosegarden for composing, so having some basic stuff like brass and drum sounds would be good too.
But if there is nothing like that in the <100$ price range, a simple low-latency midi interface should suffice.

I wouldn't mind getting a decent sound card with midi inputs either - something like the m-audio audiophile. I'd just like to hear from someone who has successfully used one of these things before I buy it.

- I should probably add that I have a Soundblaster Live Value currently installed. It has a game/midi port, but I don't have a cable, but if anyone has used its midi-in port with success that would be great since I would only need to buy the cable.

I got the m-audio 'audiophile' 2496... Works really well. 'Audiophile' is an unfortunate name. It's a really solid card that does exactly what it should. Only problem so far is that the master volume control is not hooked up right, but I can connect everything in jack... I can also configure jack now. With the SB Live I was stuck to one setting (Some freak issue, not directly related to the SB model). I had a couple of other issues with the SB Live, so I'm happy to replace it.