No way, not worth it by miles.
1) you don't get the full 40GB, a chunk is taken up for over provisioning and file structures etc. Not sure quite how much exactly but it's usually of the order of 5-10GB. Do that over 2 disks and you're not getting as much capacity.
2) they are quick enough as it is, do you really need to RAID them? And that is the only time I'd use 2 smaller drives, unless you're planning to dual boot and have one OS on each. 40GB HDD is about the min I'd put an OS on - but I'd def move the user files off the SSD and onto a HDD in this case. I'd def do it anyway come to that. (Details here:
http://www.maximumpc.com/article/how...ia_storage_ssd)
3) chances are with the vertex 2 you're getting 34nm flash still. Not sure what's in the 40GB you're looking at as link went to the 80GB model, but the vertex 2E is likely to have 25nm - and require even more overprovisioning and not be as durable in use. (Less free capacity available for you to use).
see this link:
http://forums.hexus.net/hexus-hardwa...-capacity.html
Get the vertex 2 80GB is my advice
(Or if you want to pay a bit more, get the vertex 2 120GB)
Edit: Depending on what HDD you're running that £30 could be much better spent on a Samsung F3 Spinpoint