Well, I think it's only a question of what you want to reach with your system. There are some problems with audio recording in relation to midi signal latencies. For this you'll need an real audio card in combination with a professional studio recording software which both supports the ASIOdirect standard.

If you want to record and hear your own playing a simple tape recorder is absolutely sufficient. So, if you plan to use your PC for it you can simply use it like a tape recorder. This will be sufficient for WAVE-files (audio) and for MP3-files.

If you want to hear DVDs and MP3s it could be interesting for you to buy a modern sound card which supports a 5.1 (or 7.1) surround sound like in cinematic atmosphere. But for this you'll have to buy a fitting PC sound system too (I mean the power amps). But I have my doubts that this all is available for not more than 200 $US.