I have been thinking about building a computer for a while but i wanted to keep it cheaper but have tons of room for upgrades for the future and im wondering whats the difference between the chipset 970 and 990FX.
990FX would be best paired with AMDs higher end processors. Anything from the 83xx series.
The 990FX would be best for overclocking. If you want a cheap gaming system, and you're not too interested in overclocking, grab a good 970 with a Phenom.
However, if you're looking for upgrade paths, and you might want to consider the next line of AMD AM3+ prcoessors, maybe grab a 990FX.
Depending on which kind of upgrade paths you like to have? a 990FX chipset board is allways the best choice, for the future.