SSD .... Are they worth it?

1) you can read as many from SSDs but writing will tear the flash memory until it cannot be written (erased) anymore. In the past SSDs did not have wear-leveling techniques, so if your operating system was writing to the same sector over and over, you would have a partially unwritable storage device, which will lead to problems/crashing/etc. USB sticks may also not have these techniques.

But modern SSDs like the Intel X25-M use advanced wear-leveling meaning you can write 80GB a day for the next 80 years or so. Its technical lifespan is way greater than mechanical disks and even more its economical lifespan, since an SSD can always be useful as system disk in the future. It virtually draws no power when its not being used, and it doesnt produce any noise or vibration, its the ideal storage medium!

2) SLC/MLC is the flash memory type, SLC memory is faster but more expensive, while MLC memory is cheaper but less fast for writing. However, its far more important to look at what controller is powering the flash chips, since flash memory can operate in parallel the controller is key to performance and not the memory chips themselves. So also MLC-based SSD disks could be made extremely fast with a good controller. The Intel X25-M is also using MLC memory, while the X25-E is using SLC but its more expensive and generally not worth the money at the moment.

3) during gaming your harddrive isn't used by most games, so using an SSD will not give you higher FPS. But it will shorten the time the game needs to load including loading levels etc. Having enough RAM is most important for avoiding 'hick-ups' because the HDD has to be used.

4) yes, i think SSDs are worth buying right now. Intel is dropping prices on april 26th for their SSDs so the Intel X25-M 80GB would be a real nice buy. You could also buy two and put them in RAID0 without risk, and they would best be complimented by a large 5400rpm data drive like WD Green 1/2TB, for mass-storage.