I've gone through several speakers over the past year in the price range of the Paradigm Atom and somewhat higher, all driven by the lowly T-amp. The list includes the Paradigm Titan, Visaton B200 (DIY kept it cheap), Triangle Titus 202, Cambridge Soundworks MC200, etc. I've also driven these speakers by various mid-fi receivers from Onkyo, Sherwood, Pioneer, and can say without hesitation that my original PC speaker solution, the T-amp + Atoms, is a hard combo to beat.
The Atom is not the most revealing speaker, but driven by the T-amp, it doesn't strike you as veiled either. It is very smooth and has a nice midrange to it. The B200 (used in the $1,200 Omega B200) and the Titus 202 present significantly more detail, but they don't sound (to me) as great on some kinds of music. Those speakers do sound nice on small ensemble jazz, vocal jazz, etc.
The Atom sounds VERY acceptable playing all types of music, and even moreso when driven by the T-amp. The Paradigm Titan suffers from a slightly boomy sound, probably due to the larger cabinet and woofer. If I had only around $200 to spend on PC audio and wanted a stereo rig, I wouldn't hesitate to go with the Atom + T-amp. If you have another $100, Yamaha sells a cute little 8" powered sub, the YST-SW215, that seems to play beyond its price range too. I recently bought two to go next to my 42" Sony Grand WEGA--perfect for a smaller room.
-coma
P.S. I'm not around here much lately--PM or email me if you'd like to discuss.