FWIW, you can automatically sync the G1 with Windows Media Player 10 without the need for 3rd party software. WMP10 sees the G1 as an external media device and will sync what you throw at it.
I'm using iTunes to read from an external hard drive with my music on it, getting 1 set of music onto my iPod, and with WMP10 and a G1 with a much smaller storage space, I'm using WMP10 to just sync specific albums
Works like a charm.