Liz: Heres my suggested parts list that may fit your budget.

Athlon 64 3000 +
Asus/MSI Board
1 - Gig RAM (Preferably 1-stick)
80+ Gig HD (get the SATA)
PCI-Express Vid Card
17" LCD (if your cramped for space)
52 x 32 x 52 CD writer or better yet a DVD-Writer (again depending on your budget)