Since OS X does not yet (ever?) support TRIM, make sure you get a drive that supports Garbage Collection-- to help keep performance up.
A few thoughts:
1. The Vertex 2 has a reputation for speed, but the company just switched to 25nm NAND from 34nm (just like everyone else will probably do too, eventually) without changing the labels on their product. This has caused an uproar (See the OCZ forums) because the 25nm NAND has a shorter cycle-life. To balance this out, more space from the drive is set aside for over provisioning (you can't use it). Also, the number of IC used for each drive has halved on the smaller drives, meaning you get significantly lower performance.
In real terms:
60 GB drives show 55 GB BEFORE formatting.
Sustained write speeds have dropped, in some cases, to 37 MB/s some ppl are reporting.
*Go read the activity on the OCZ forums to check these figures
2. The Crucial C300 is a great drive for Windows, but not Macs. It relies on TRIM, so there's a good chance your performance will slow in OS X over time. Also, it's SATA 6.0 won't help you (at least now) since OS X will only support SATA II speeds over SATA 6.0 hardware for the time being.
3. IOPS, read vs write, compressible vs incompressible data. These are important terms to understand when trying to pick an SSD. Higher IOPS is better, and some drives, like the Vertex 2 claim 50K vs 10K for competitors; this should help with the typical kind of use a boot drive sees. The economical way to purchase right now is to buy an SSD for a boot drive and store media on HDD; this plays to SSD's strengths, which are quick reads as opposed to massive writes (shortens lifespan, degrades speed on most SSD, even with TRIM or GC). Sandforce based drives appear to have faster read/write speeds, but they compress data... so incompressible/compressed data is much slower to write. Another reason why using SSD for a boot drive make sense: you're dealing with at least partially compressible data, as opposed to compressed data like most media files.
Blah, blah, blah... sorry for brining all this up and rambling. But I wouldn't buy an SSD without reading up a bit-- particularly on OS X (because of the lack of TRIM).
