Originally Posted by latrosicarius 
no........... your quality is not worse with a USB mic
The question is... with the advent of USB microphones and speakers which keep the signal digital for longer... what use is a sound card?
Now, if the sound card had USB pins/plugs and was able to accept the USB microphone and process it FOR the cpu, THEN, a sound card would be good to have still
There have been latency problems with USB mics. OK if you spend enough then it's probably good, although you miss a certain amount of functionality. But keeping the signal digital for longer is no magic panacea - if the equipment that turns that signal into analog is crap (which is the norm for cheaper USB equipment) then the end signal is still crap. In general buying USB mics, headphones or speakers gets you worse quality for more money.
Moreover, there is absolutely no point in a soundcard having USB connectors, because the USB equipment acts as its own soundcard.