I think flax is great. Its a good source of Omega 3's or EFAs. Fish is better though; Its also holds a higher boiavailablity. "Health from the sun" carries a nice Flax, Fish, & Borage oil containing all your Omega's (3,6, & 9). Its 9.99 for an 8oz bottle.
If I had to recommend anything, however, I'd say fish. Fish contains a higher EPA and DHA content. I get a 300gelcap bottle for 6.99 & take 9 to 12 caps a day.
The EPA and DHA in Fish as also been shown to help reduce fat at doses 3g and up. That's about what I take, 3g to 4g ED.