Stanley makes a great fan, I keep it on the low setting and it's plenty strong.
That's the one I keep seeing in use. It's a much more road-worthy fan than any other I've had, and the built-in adjustable angle lets you put it almost right underneath your throne when space issues require it.
If you can't find something similar locally, search Amazon for 'Lasko blower' (Lasko manufactures them).
Check out the BlowIt fans. They're specifically designed for drummers, and clamp straight onto your cymbal stands (very nice on cramped drum risers):
http://www.blowitfans.com/
I have an older model Lasko blower and it was great. It actually just broke last week only because somebody yanked the cord out of the wall and left behind one of the prongs. I had it for 3 years and abused it. I play 150 dates a year and many of them are outside gigs in texas in the summer. I leave it on the high setting every gig, just make sure its not blowing on a mic. They aren't that loud, but they move a ton of air!
The last gig I played when it broke I was sweating so bad I didn't realize how much it helped!