Join Date: May 2014
Location: Maple Ridge, BC Canada
Model: 97 gl1500 SE
Don't be tempted by the cheap Chinese stuff on eBay. Been there, done that. Most of them were not even as bright as the stock incandescent bulbs, or had a really bad light pattern. I got lucky with some, after trial and error. Keep in mind that putting LED's in on turn signals (i know you didn't mention this) will require ballast resistors (I don't recommend) or an electronic flasher, otherwise you'll get no flashing or 'hyper' flashing.
SuperBrightLEDs.com - as Dave referenced - are a good place to start, as they actually list brightness levels and field (width) of light. Most housings have reflectors designed for regular bulbs and putting LED's in may not put the reflectors to good use - making them really bright directly behind you, but not bright at all if viewed off-angle (anything other than straight behind.)
Bikes I've owned since June, 2013:
Since sold:11 CBR250R, 89 ZG1000, 92 Ninja 500, 85 V45 Magna, 84 DT200, 82 Virago 750, 92 Virago 1100, 04 Kawasaki ZZR250, 07 Vstrom 650 ABS, 88 GL1500, 14 Ninja 300, 86 V65 Magna, 96 VLX600, 08 WR250X, 09 KLX250S, 87 FZR1000, 14 Ninja 650, plus some more...
2010 Husqvarna TE250
2015 Kawasaki Ninja 650
2008 GL1800 with bagger kit