It is very close and there is not much in it. They are both about �399 give or take a few pennies.
The CPU in the Toshiba (T2080) is slightly faster than the Acer CPU (T5500) but there is so little in it to be not worth bothering about. But the Acer is a Core 2 Duo CPU which is better
The Toshiba has a 120Gb harddrive as opoposed to the 80Gb in the Acer.
Apart from that they are exactly the same (1Gb of memory, Vista Home Premium, 15.4" screen etc)
Both makes are well known so there is not much in that, and they both weigh about the same.
I cannot see what software comes on the Toshiba but the Acer comes with MS Works 8.5 AND a *trial* version of MS Office Home and Student Edition.
So not much in it either way, with the Toshiba seeming to be slightly better (but not by a lot, mainly hard disk size).
So it comes down to which one you fancy, and which one is easiest to buy - the Toshiba you can buy in store I think, the Acer I think is delivered so there may be a delivery cost.
Toss a coin.