Fell in love with this one the first time I typed on it, dropped the $130 and have never regretted it. The noise and feel of the typing is unparalleled.
Has USB ports on the side. Performance-wise, response is apparently faster if you use the serial port connector rather than the USB adapter... can't say I've ever noticed the difference.
Only downside is there are no media keys-- if that's something you care about. The one with no markings looks bad ass to boot.
Would highly recommend.