MXL USB 006 - http
/www.amazon.com/MXL-USB-Cardioid-Condenser-Microphone/dp/B000JUFEDO/
Audio-Technica ATR2500-USB - http
/www.amazon.com/Audio-Technica-ATR2500-USB-Cardioid-Condenser-Microphone/dp/B004QJREXM/
MXL-STUDIO 1 - http
/www.amazon.com/MXL-Mics-MXL-STUDIO-Condenser-Microphone/dp/B00684PYFS/
Blue Snowball - http
/www.amazon.com/Blue-Microphones-Snowball-Microphone-Aluminum/dp/B002OO333Q/
If I was going to get one, I'd get the MXL 990 USB. Some of those I listed are a little above your price range, but well worth the extra $20-$30.
My highest suggestion is the MXL 990 USB, second highest would be MXL USB 006, third would be simply the Snowball.
If you want to go high end USB: http
/www.amazon.com/Blue-Microphones-Condenser-Microphone-Multipattern/dp/B004L9KLT6/