well math:

the Live is about $40 and the audigy2 is about $70 OEM ... so only $30 diff,

the live is fine, BUT the audigy: has noticably better noise characterics, has significantly lower CPU utilization when doing 3D sound, has more headroom (about 4x the processing power) for handling sound in the games of tommorow ...

now of course, only the noise characteristics matter on a good machine, but if you have a slightly older machine (like 500MHz to 1.2GHz) - then the CPU utilization might matter to you a little. It all depends on what $30 means to you

The low-end (read:non-professional) cards from M-Audio are absolutely fantastic, plus they tend to have much better driver support than Creative.
Of course, they also produce professional cards and audio hardware so you''d kind of figure that they''d be on top quality wise.