Intel SSDs are great (I own one myself), but they don't have the fastest speeds. Get either a Mushkin Enhanced Chronos Deluxe 120GB or a Kingston HyperX 120GB. If you wanted more space, you could go for a Corsair Force 3 180GB. The Muskin has the fastest speeds at 560MB/s for reads and 515MB/s writes. The Kingston has 550MB/s and 515MB/s, and the Corsair has 550MB/s and 515MB/s. So their all relatively around the same speed. The Corsair one is a little better in $/GB, but you can't really go wrong with any of them
With the same SSD you have three options to go with , a just SSD , a desktop upgrade kit or a notebook upgrade kit. Same SSD just three options all the same price. So you can go with either the Intel or the Samsung SSD. I have had Intel SSD's amd found absolutly no problems with them and they were the early models at that.
The 128gb size will give you enough room for the OS and a few games along with your most used apps. Personaly I think that the best size for a main boot drive (C-drive) is a SSD of 240gb , however the cost is high enough to drive most people to the lower capacity SSD's. So for about $200 you will get a 128gb SSD and one that is very stable and reliable.
Yes , as I said I have had the Intel SSD's previously and they were no problems at all they were rock solid. They were the SLC version that were the first ones to be listed for sale along with the Samsug SSD's and it was a choice to go with either the Intel or the Samsung. I don't think you can go wrong with either one because they are both good quality and both have been producing SSD's from the start. I just think that Intel has put more effort all along while Samsung kind of dissapeared for a time but they are back. The new Cherryville line now uses Sandforce controllers.