I have had good luck with SSD's.
I own ( 6 ) of them ( 3 x OCZ 40GB Agility2, 60GB Vertex3, 90GB Agility3 + 2 Corsair F40 40GB, F60 60GB, and 1 x Crucial M500 240GB ).
They work well for booting systems fast, as well as loading large games fast. However if you do video editing etc such as I do sometimes with large files, this is still best performed on a HDD instead of a SSD to avoid overworking the cells.
I'd highly advise installation of both a SSD and HDD in the same system. SSD as C: and say HDD as D: . Place your OS on the SSD, and any games that you want to load fast on the SSD as well. Music, Videos, Personal Data, etc, I would store on a HDD where you should have plenty of storage capacity.
All but 2 of my SSD's are in systems used as C: drive along with a HDD as D: . I installed a small SSD into my wifes Core 2 Duo E6600 system running Windows 7 32-bit on 3GB DDR2 667Mhz RAM, and it drastically improved boot time. Since the SSD is small, I placed the OS only on this SSD and programs and games are installed to the 160GB HDD which is also where personal data is stored to keep this small SSD free for room to grow with Microsoft Updates etc. I also moved her swap file to the HDD vs the SSD to free up 4500MB of space on the SSD to instead be allocated from the 160GB HDD instead.
There have been some good deals on 240GB size SSD's lately, so I would not go with small SSD's. The main reason for buying the small ones that I bought was that it was a cheap way to get the performance of a SSD without spending crazy money since some of them were bought 3 years ago when SSD's were most costly than they are today. Such as the 40GB SSD's I bought for like $30 after rebates etc. My latest drive the Crucial M500 240GB though is the better drive for longevity in a system to where there is room to work with it and not run out of space for most applications. I installed this 240GB into my Toshiba laptop to increase battery life as well as speed up boot and load times of games.