I'm a PC but I'm thinking of becoming a Mac. An iMac to be more specific and iMacs don't have replacable soundcards ( or graphics cards....booooo).

Anyway the good news is that iMacs support USB and that they have four precious slots. Being an audiophile I am simply not interested in putting up with 'onboard' sound and I have thought about using a USB audio interface as my soundcard.

My question is have any of you done this and did you notice an improvement in audio quality?

Otherwise part of the whole awesome sound requirement would be lost meaning I might not want be Mac and that I might want to continue being a PC but with a very nice X-Fi Titanium soundcard.

I was thinking Line 6 UX2 or something similar (I think UX2 is discontinued now and UX8 would be overkill because I'm a newbie at recording).

Answers, advice and comments welcome.
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The UX2's are fine and still being made AFAIK, the X-fi soundcard is not a pro-audio card, its a pro-consumer card. First decided if you want to go pc or mac. I would suggest staying pc, simply because mac's are way over priced for what you pay for them and a pc can do any of the audio stuff a mac can, but either way, thats your choice.

Decide on what you want to be recording. How many inputs at once? How many outputs? Is this for recording you jamming or a full band? The nice thing about the line 6 is you get pod farm which is a pretty good amp modelling plugin to use in a DAW of your choice, but it also functions as an interface as well, so you get a good deal IMO with them.
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well I know the creative card is nowhere near pro audio but I just like to hear good recordings and listen to my music collection with something other than bog standard sound cards.

I still want to know how audio interfaces perform (quality wise) as soundcards. Someone said to me they had done it but then again this was in a shop and were probably trying to get me to buy it. The kid didn't really look like he was sure.
I collect clothes and IKEA furniture. Who are you?
Imacs have firewire 400 and 800 now, and supposedly there's a company or two building a workaround to use both linked, with a total of far more than 1200.

USB 2.0 =antique!