Running 7.1 on a stock board makes sense, since you can't go any lower. I wouldn't go up to 7.5.5 because you're really going to notice the slowness of the machine there. If you plan on upgrading to an LC520/550/575 board or adding an accelerator then 7.5.5 or 7.6 would make sense.
If I'm not mistaken the 8.x Appearance Manager won't work with 7.1, though I think it does with 7.5.x and 7.6.