External sound card buying advice

I am considering buying new external sound card and need your help to get the best one. Well, after going through online search and reviews I have narrowed my choice down to Creative Labs Sound Blaster X-Fi and ZALMAN ZM-RSSC. Both are 5.1 Channel, have almost similar specs and available at http://www.dealrocker.com with good discounts. I want to know your views and advice before getting into anything. If you have any better recommendation, please let me know.

Thanks in advance.

Those choices are probably OK for gaming/internet playback but for any serious audio work involving recording sound something from say the M-Audio range would give you much better quality sound. Also don't be fooled by the 5.1 surround tag on your selected interfaces. They will probably only reproduce surround from Dolby encoded material, they won't enable you to use 6 discreet channel outputs from Audition.

Before asking for advice on such a purchase, it would be good if you were to outline what it is you require it to do and budget limitations.

Broadly speaking, I wouldn't consider either of these for quality audio work - but it does depend on quite what it is you want to do.