This little guy has been with me on every ride I've taken (minus races) for almost two years now. I've used this for flats out on the road at least 8 times in that time.
SPECS: 102g / CLAIMED MAX 120psi / $44.99
Before this I've had CO2s and other hand pumps. CO2s make me nervous because I've seen guys blow out their tubes, and have multiple flats and run out of cartridges. The other, smaller hand pumps I've had worked OK, but really couldn't get the PSI very high. I decided to buy this one because it could get the PSI much higher, which is important if you get a flat far from home. Otherwise you run the risk of getting a pinch flat on the way back home (it's happened to me).
Tubing is enclosed in the pump, and you remove that and screw it into the other end. Then you screw that to the valve and start pumping. When you've gotten it inflated as much as you like, you simply unscrew. The tube is excellent - an issue with other hand pumps that attached directly to the valve is the wheel is moving all over the place at the end when you're pumping the hardest you can. With the tube, you can pump it really hard and you have a few inches of movement before you'd move the wheel.
So does it pump up to 120psi? Maybe, but I've never done it. I've easily pumped my cross tires up to 50psi. In a test I did for this article, it took me 1:30 to pump my 700 23c tire from completely flat to 50psi, and it would have been pretty difficult to get it higher than that. My arms aren't exactly muscular though. Regardless, that's higher than I've ever gotten it using other pumps for sure.
The only complaint I have is that it's tall and sticks out of my back pocket when I'm riding. But the length is also what makes it able to fill the tires so well. So I've opted to look a little less pro for piece of mind.
PROS: Light, actually pumps your tire up. Tube makes it easier to pump.
CONS: Doesn't look pro sticking out of your pocket. A little expensive.
RECOMMEND? Yep, I'd recommend these. It works, and that's about all I need it to do.