I just got a new Dell E6500 with all the options including SSD Drive..
It's totally worth it.. boots Ubuntu in 7 seconds with a standard install (no tweaking)
ssd's vary GREATLY, read and write speeds change the price of for exmaple a 64g drive from £100 to £300.
i have the offical dell 64 ssd for sale on here actually, it's pretty medium range, but is good value for what it is, priced around the £100 mark. I have in my gaming pc a higher spec one for £200 and yes, the difference is quite noticeable. You hsould do more research i would say.