Windows 7 - Buy a HDD now or later?

So I am planning on buying all the parts for my new build in a couple months or so. I have some questions, first off is buying everything at once the way to go? Because I want to get a 1.5TB WD Caviar Black HDD which could be used in my current setup but is ultimately meant for my new rig when I have all the parts, what do you guys think? Should I buy the hard drive now or with everything else, it doesn't seem like much will be improved in a few months on hard drives. Also with cases, I was going to get the Cooler Master HAF 932 since I don't really see cases improving much in a few months. One thing I will take note of though is that Ivy-Bridge is supposed to be released around March-April time so I would look out for that but otherwise what do you guys think about buying some stuff early? Thanks!

It's normally best to buy stuff all at once at the last possible date---so you don't have some Dead-On-Arrival parts sitting on your shelf for months, when you don't yet know they are DOA.

However, if you have a way to determine if the parts are good when they arrive, you don't have to worry about DOA.

Mechanical hard drives are now about triple what they were a few months ago due to flooding in Thailand, so you may be better off waiting. But prices may remain high for longer than you want.

Oh yeah, forgot about the whole DOA situation although I would probably just use the new HDD in my existing setup until I have all the parts for the rig. But you do make a good point with the whole flooding thing.

And ivy bridge will be very expensive to buy into when new, look at the e-sandybridge range £450 for the lowest spec CPU at current, and £900 for the best...

I would buy an SSD either way, prices falling, and will be the difference between night and day on your new rig, why have a fast processor and ram if you don't have the hard drive to match.

And wait a while for the 1.5tb, prices will fall at some point, they are very slowly. I might buy one when they are around£80, which is still roughly double what they were originally. But I only have a 120gb SSD in my gaming rig, so will run out of space eventually