The arcade isn't worth it IMO, you really need a hard drive. If you look around you can get a 60GB model with Quantum of Solace for £130. Picked one up in Curries Digital Megastore in Lakeside.

Does the 360 arcade machine come with the jaspar chip inside? i already have a 20gb hdd.

They were supposed to be the first lot with the Jasper chipset, so if its a newish production model then probably yes.

j.o.s.h.1408;1837193
Does the 360 arcade machine come with the jaspar chip inside? i already have a 20gb hdd.

Just ask the CSR to look into the hole on the box for a 12.1a rating then you will know its a Jasper.

PS This might also be useful for you.