Still new to Macs, need hardware advice.

I'm still kinda new to macs, have only had a macbook for about a year now. I'm going to be purchasing a new iMac to finally replace my PC desktop computer (thank god!) but I had a question about prices and upgrades and such.

I'm really familiar with PC hardware but not much so with macs. I've been pricing the 24in 2.4ghz imac and was wanting to upgrade both the the ram and the hard drive. Apple sells the ram upgrades for 2gb (add $150) and 4gb (add $850). I've looked up the same exact ram at crucial.com and they're quoting about $50 for 2gb and $140 for 4gb. What gives? from what I can tell its pretty much the same ram or is there something i'm missing?

Also I wanna get a 1TB hard drive for the system. Are the same serial ATA ones I can get anywhere? are they a special size for the imacs? Would you reccommend me buying my own and installing it.

Thank you very much for you input!

Apple's prices for RAM and HD's are so expensive. Go to google, type in the type of memory and it should come up with the cheapest on the web. I bought and installed my own memory in my iMac (2, 2G sticks). The hard drive is a different story. I would go ahead and just get the 1TB already installed shipped by Apple. Getting to the HD on the new iMacs are very hard and I wouldn't want to break the warranty.

FYI- If you install the RAM by yourself, make sure you know what you are doing. Or find someone else that knows how to do it. because if you break something, it voids the warranty.

crucial is a great place for ram, a SATA drive is a SATA drive. There is no such thing as a PeeCee only SATA drive. Apple's prices are high because some people like the security of not googling web sites in search of things such as a 200 pin PC2-5300 667MHz DDR2 SO-DIMM. It scares them!

Thanks guys for the great advice. I think i'm going to go with what EuphLlama advised. I'm pretty sure I can handle installing the ram if its as easy as it was for my macbook. I didnt realize the difficulty and warranty issues when it comes to the hard drive.

Thanks Sherman as well cause who knows down the road when theres such a thing as 4TB hard drive i may want to open it.

-Keith