Best performing/value SSD or duo, at 40-100GB?

[naokaji]

What interface does the x25-m use again, forgotten, it's SATA2 right?
Is it known to be hamstrung somewhat by it? (like in random bursts etc)

Yes, it uses SATA2 and no, its not really limited by it. The Sandforce drives are using SATA2 only as well, if you want SATA3 you would be looking at the Crucial RealSSD 300, but that is very expensive and performance is not consistent.

When can we expect vertex2 and what are the significant differences between SF-1200 and SF-1500?

Unfortunately there is no final date set in stone.
The performance difference is small, while the price difference is said to be massive, but then price will be a issue for most sandforce based ssds as they have lots of "spare" nand to reduce the negative impacts of usage.

Actually given my previously mentioned usage scenario, I'm having a hard time determining if 50GB really is sufficient.
I'm starting to think 60GB is the ideal minimum capacity; just to be on the safe side.

The x25m is 80GB, so you would have some more headroom there, intel limited max write speeds artificially to make the x25e look a bit better, but in worst case situations where other ssds tank like crazy the x25 (both m and e) just keep going which makes them overall very attractive drives.

Of course there is another option, with the release of the sandforce armada getting close you should be able to find the current Vertex (and its identical counterparts from the competition) with some nice rebates which may allow you to go for more capacity.

Newegg currently has some nice rebates on the 30GB vertex, since Intel just released a chipset driver that supports trim in raid you may also consider putting two 30GB Vertex in raid 0.