Dont skimp on your hard drive. The hard drive is the single biggest bottleneck on desktop performance. Opening programmes and manipulating files is not governed by your processor your RAM or (as someone once said to me) by your uber-expensive graphics card. Lesson from this; put some thought into which one you buy, and dont go for the 'green' versions of drives if you want a decent amount of performance.
The 750Gb spinpoint has the same 3 platter stack as the 1Tb model with identical 32Mb cache with an 8.9ms access time.
Proponents of WD or Seagate will point to their longer warranty and enterprise earned reputation but I have never had one of my spinpoints fail (for whatever that is worth).
Overall I use the spinpoint F1 as a baseline drive. Even normal users will appreciate the increase in performance over the cheapest drives availible and most advanced users and gamers dont require the higher throughput of Raptors or other high capacity drives. (But there is always the option to RAID a couple together)
Several years old now, the design is still flawless. Although it was born at the same time as those horribly made 1Tb drives from other manufacturers (The Hitachi being the worst offender) the HD753LJ did not stretch older technology to increase the capacity to the terabyte milestone. Because of this it has outlived the competition and deserves its continued place in the Samsung lineup.