Well I suppose it really does depend on how much space is needed Ali right now down here the SSD's are getting very reasonable

Plextor PX 128 M5S - $90 and the 256 $179 similar prices for the OCZ Agility 4 & SanDisk Extremes.

Personally I like the Samsung 830 range but apart for the 120Gb $105 start getting a bit pricey.

Still have a small one for boot and an external for data at least you will not have the noise problem.:)

But I still think a 500GB 2.5 HDD (about $75) in a tray will not be as noisy as the 3.5 ones but thats just my opinion