Need some advice on upgrading my hard drive

[obsol33tsniiper]

I currently run 1 Western Digital WD20EARS Sata ii hard drive for all of my computer storage. I am thinking about upgrading to a Western Digital WD6000HLHX Sata iii 600gb hard drive for storage and a Crucial RealSSD C300 CTFDDAC064MAG-1G1 Sata iii 64gb SSD hard drive for my operating system and other main programs. Would I see much of an improvement with the SSD over the WD6000 if I were to seperate them or should I just get 2 of the WD6000's? on eBay a new WD6000 is $167 and the C300 is going for around $120-$130 on various websites. I ONLY want to have 2 hard drives in my case because I have the CM690 Advanced and I took off the removable hard drive slots to add space for a bottom mounted liquid cooling radiator.

 

[obsol33tsniiper]

Also I could just get one of the WD6000's until I actually need the space. For now I do not really need more than 300gigs for all of my music, games, and programs. I will shortly in the future be programming games and other things like that so I will be using external hard drive so that stuff will be portable. I just want my main rig as fast as possible while not wasting money if the speeds are very similar.