I could tell the difference between 48 and 44.1. It wasn't huge, but it was enough that I would still be using my cd player if I couldn't get 44.1. I don't know what all soundcards can get 44.1, but my card (the chaintek) was only 25 bucks or something close to that.

I will say that it was a pain to get it to switch to 44.1. I had to closely follow a thread over at avsforum that explained it step by step using the ASIO plugin. I didn't work a few times, but eventually I got it and it's been good to go ever since.