Okay Integrated GFX, that doesnthelp. 512 MB RAM is the required not recommened stats.
Basically i would say Home Basic. It doesnt have Aero, which your integrated graphics cant do anyways. It willb e sluggish since it has the least amount of RAM required.
Home Basic would be your best option. I have seen systems running with 512 and integrated GFX and Vista Home Premium and they were slowwwww. About 10 minutes to boot.