I'll probably get the 840, is there anything similar price range with faster read speeds? :O
For an extra £10, the Toshiba would be my choice.
YOUR BASKET
1 x Adata XPG SX900 128GB 2.5" SATA 6Gb/s Solid State Hard Drive (ASX900S3-128GM-C) £95.99
1 x Toshiba SSD HG5D Series THNSNH 7mm 128GB Solid State Hard Drive - (THNSNH128GCST) £94.99
Total : £200.58 (includes shipping : £8.00).

- I currently am booting off a 320GB (newish)WD blue 2.5" - the system is pretty newly installed, for some reason though, it tends to boot very slowly and sometimes totally freeze out for no reason, could this be a dodgy HD or could it be a dodgy HDD controller on my mobo?

Unless it goes wrong...