SanDisk Extreme SDSSDX-240G-G25 2.5" 240GB SATA III Internal Solid State Drive (SSD) for $169.99 + free shipping
I picked up one of these drives recently and love it so far. I read a comparison of a number of SSD drives and this one wound up ranking 2nd (I think it was out of 10 or 12 SSD drives, not sure), it wasn't the absolute best in any one category but ranked high in everything they tested.
It's plenty fast and really helped speed my computer up. With one of these and a 1-2 TB drive your computer will have reasonable capacity and faster load times.