Maybe I am a little behind in my terminology...
I know what small form factor is. I have never heard of low-profile until today. Are they the same thing? ...or does low-profile simply refer to a form factor smaller than the traditional full size form factor?
SFF is generally anything smaller than a standard ATX case. Low profile cards are used to fit inside small form factor PCs, though some SFF PCs may have low profile height PCI bays that you shoudl watch out for.
Core 2 Duo E6600 @ 3.40GHz w/ Silverstone Nitrogon NT06 (both lapped)
ATI Radeon HD 4850 @ 690/1150
ASUS P5K-E WiFi/AP Edition, 4GB DDR2-800
Gigantic server case
150GB Raptor, 150GB Velociraptor, 2x 2TB RAID1
Creative X-Fi Platinum
Enermax Aurora, Logitech MX1000
Envision EN2028 20" 1600x1200
Custom built speakers