I bought a 200 lumen Cygolite Pace earlier this year. Pretty happy with it, but being a proprietary design, spare batteries and mount brackets are a little pricey. I bought one extra bracket to use it on 2 bikes.
More recently I picked up a 208 Lumen
coast px25 for $40 at Home Depot. Nice beam pattern. A very clearly defined bright circle in the middle and a larger circle about half as bright surrounding it. Uses AAA batteries, which according to Coast should last about 6 hours. So spares are cheap and easily carried. (I do realize many folks here don't like lights that use AA or AAA's) Mounted with a rubber and velcro handlebar mount costing $2.60 at Dealextreme. About the only minor downside is it doesn't have a flashing mode, but Coast makes a similar model with flashing and adjustable beam pattern for about $10 more. The internal contacts seem well designed and I don't expect this to fail like some cheap flashlights I've had in the past.
I put both of these lights together the other night and 400+ lumens lit up a dark trail quite nicely.