One thing to keep in mind with these drives and the specs...is that the specs list the sequential read and write speeds of the drives. So, while lots of other drives have much faster sequential write speeds than the Intel drives...the Intel drive really shines with random I/O writes and that is what happens 95% of the time that you run applications and your OS on the drive. Thus, even though the specs are lower on the Intel, the Intel almost always wins out in benchmark tests and such which expose real world usage.
You might want to keep your eye open for the Intel X25-M G2 80GB drive. These can be found around the $250-$275 area and would give a huge performance bump over your existing drive without having to implement a RAID array to have sufficient storage space available.