You mention the Inno3D 256MB card, but which one? They do many different cards quite a few with 256MB.
It really depends how much you are willing to pay, for the likes of the Microsoft flight sims you don't need to spend a huge amount on a top of the line card.
Could you perhaps give some idea of a budget? The Nvidia 6600GT is good and its just under the £100 mark, I've just got a XFX 7600 GS which has no fan, I got it to replace my 6600GT which failed, slightly more pricey by about a fiver but it has no fan just a mega heat sink. I've only had it a week and its good, haven't had to try the overclocking yet (its built in by the way as I would never try it otherwise) but I do have concerns about the temperature. On heavy load it reaches 95 degrees, never goes above that and from what I have read it is normal for this card, its about 10% better than the 6600GT in tests. Links 6600GT click here the 7600GS click here thats what I now have and a slightly cheaper one click here