If you can get it cheap and it will work, go for it.
My computer is a 3.2GHz Pentium 4 HT 1MB L2 800MHz FSB. Its the fastest computer I have since I killed my Athlon X2. Sure its not a mind blower, but its got enough power for most tasks outside of heavy gaming.. With my nVidia 9800 GT I can play 1080P Movies!