Reviews
here include hardware and software.
There are also reviews and comparisons at
www.gpspassion.com.
I'd suggest a BT unit to reduce the wires and get one with good sensitivity. Given you are running, you want light weight, so the GPSlim 236, GlobalSat 338 or the new RoyalTek 2001 should be good. GPSPassion also says that SysOnChip is making one that is a keyring sized device.