I've used a couple but right now I use a Topeak Mini-18. It's the best bike multi-tool I've ever used.
My every day multi-tool is my Schrader Tough-Tool. It broke my heart when the company went under. They made great stuff, and that multi-tool, despite the fact that it's 10 years old, is still better than the current leatherman's as far as I can see.