I've been using Niterider for a few years, first a rather big 250 lumen light, then smaller Luminas (220 and now 650. Battery life on the 220s is starting to slip). They're a good company, too - I dropped the 250 and cracked the lens; they fixed it and sent it back for no charge. Later on I boogered up the USB port on one of the Lumina 220s and same deal - fixed it and sent it back for free.
Also, I always buy "older" lights (though still brand new). I got the Lumina 650 for $30 new on eBay.