I've got one of these external boxes:
http://www.ebay.com/itm/221681003044It's USB and has headphone, mic, line in/out, SPDIF, etc. but it's absolute garbage. I can't believe they cost about $90 new. I can actually plug a pair of headphones into it and go around the room finding RF interference hotspots with the buzz it produces. It's really sensitive/directional for that usage scenario but not really what you want in a sound card.
It also has an incredibly bright blue LED on it that
flashes when it's receiving audio - absolutely useless in a dark room
Maybe I should send it to Dave for a teardown and laugh.
(or maybe I could try and get $25 for it on eBay)
I swear I'll never buy another Creative Labs product as long as I live. I once bought some of their "THX certified" desktop speakers because all the PC magazines were going crazy giving them gold stars that month. The sound was so bad I actually felt guilty about selling them on eBay the next day in case a musician bought them or something. It doesn't give much confidence in PC magazine audio reviews either.
PS: I can put my cheapo PCM2704 DAC right next to the WiFi router and it's completely OK (presumably because it's in a metal case).
The PCM2704 also has about 8db more dynamic range than the AD1825 used in that SoundBlaster - winner, winner, chicken dinner!