Just got myself a denon sc7000. I can't recommend it enough, it's fantastic! Best investment I've ever made. I'm a very happy boy, after just one day I can't imagine how I ever worked without it!
I've tried a few things before, used to have a weller wand thing with external pump unit. That was crap, used to get clogged up all the time. Then the heater packed up and I couldn't get hold of a replacement from weller. Take note...
I had one of these cheapo chinese ebay ones for a bit.
http://www.ebay.co.uk/itm/Brand-New-Hot-Air-Gun-Electric-Desoldering-Repair-Tool-Kit-220V-240V-/261104711503?pt=UK_Home_Garden_PowerTools_SM&hash=item3ccb0db74f
When it works, it works pretty well, but after a year it's on it's 3rd heating element and 2nd pump motor. Spares are cheap but there's a line somewhere where the time spent maintaining the thing is more than the time it'd take to just use desoldering pump/braid for desoldering anyway. And it's not very safe, no fuse or protection circuitry in there. If any of you do get one of these make sure to change the fuse in the plug for 1A or less, mine came with a 10A. The PWM controller packed up and put full mains voltage on the heater and it overheated and melted the plastic housing. Time to chuck it in the bin.
If you're really on a budget...
http://cpc.farnell.com/jsp/search/productdetail.jsp?id=SD0170205&Ntt=SD0170205
Novel idea, haven't seen them before. I got one, it works ok. Heats up pretty well. Bit easier than using a desoldering pump and an iron. The opening on the tip is about 2mm, not very precise. Seems like it's a new product idea and they haven't started making different size tips yet. Make sure to keep the tube clean, it gets clogged easily. But for £5 we can cope with that, buy a few for spares!
If you have the money, get a denon. I've just started replacing the switches on a console. 2200 odd switches, 35000 odd pins to unsolder. I tried doing one channel with the cheap chinese desoldering gun, it took an hour. With the denon it took 20 minutes. What can I say!?