All video cards work with all modern processors
whether it be Amd with an intel cpu, nvidia with an intel cpu, amd with an amd cpu, or nvidia with an amd cpu; it all works together.
Unless you are going to be handling ridiculous work loads, and rendering multi-billion cell spreadsheets, then there is no processor that can even compete with the 2500k in that price range. It is hands down the best CPU for gaming, side by side with the 2600k. So yes, the 2500k would be the ideal option as its unbeatable by any AMD for that price.
Also, you may wish to wait until april 29th when intel releases their Ivy Bridge cpu architecture. It will bring up to 20% better performance than the Sandy Bridge cpu's (which the 2500k is). Right now the 2500k is going for 220$, when the 3570k (the ivy bridge version of 2500k) is released, the 2500k's will go down to about 150$, and the 3570k will be at 220$. In my opinion it is well worth the wait, though that is for you to decide.