Amphipods are good because you can get a lot of different styles and buy attachable pieces for storage. I bought an extra large pouch to attach. I have a camelbak I use for hiking and trail running, they are good too; however, with something on your back it could affect your posture and your gait could also be affected. If you are doing primarily road races, the amphipod is the better bet. Most stores you can try them on and run around inside to get a feel for them too.
If you are concerned about carrying strips, meter, etc you could check out raceready.com, they made shorts with many pockets that are easy to run in but carry a lot. They don't carry water, but have a lot of pockets for the things you need on the run, I have carried my meter with me in those shorts and been just fine.