Barnabas,

The EMU-404 sound card is excellent to connect a mic to, and has 192bit sampling. Very quiet and flat. http://www.sonicstate.com/news/shownews.cfm?newsid=1766

Coupled to the Behringer EMC8000 measurement mic:
http://www.behringer.com/ECM8000/index.cfm?lang=ENG

Then add the True Audio RTA software and you are away to the races: http://www.trueaudio.com/rta_abt1.htm

By the way, these are all available for $99 bucks online.

hmm, maybe the 990 will come out for $99...