I've only been refunded a few times, I prefer to owe a little than to give the bastards more than I have to. :-)
That's definitely the best, and smartest way to go. It's surprising how many people would prefer to give the Gov use of their $ for free, just so they can get a fat refund back.
In my case, I try to trim it as close as possible, but allow a margin to avoid having to pay penalties if I underestimated too much. So far I haven't, but I always wind up getting a little something back as a result.
I still always give some thought to purchases I expect to be making in Q1 of next year, and move them forward to end of December, unless I know I'll need the expense later to help offset anticipated gains. YMMV.