NogDog is correct, do not buy the "latest and greatest". If you're on a citizen's budget.
All I need is speed for programs like Dreamweaver, Firefox, etc. Which is more important, CPU or RAM? Also, does harddrive play a role in speed?
My short answer is this:
The CPU(s), RAM (amount and speed), and hard drive(s) all work together with the motherboard to get things done. If one of the 4 is slow, the overall performance will suffer. A $50000 processor won't speed up performance if you have $5 worth of RAM and $20 drives (with a few rare exceptions). Likewise $50000 spent on RAM, drives, and a motherboard wont work well with a $5 processor. They probably wont even be compatible.
At a certain point you do NOT want more RAM, you want faster RAM. All RAM was not created equally, some of it is trash and a lot of trash is bad. Same goes for the hard drive: do you really need 1TB of storage, or is a lightning fast 20GB hard drive enough. If you're stuck between the two, you might consider striping drives with a raid protocol. Your motherboard need to support what you get. If your RAM is too good, you might need to configure how it handles it in the BIOS.
Windows 7 scrubs all of the RAM on start-up. So when you get 16GB of RAM and want to know why it takes you forever to boot up: that's why.
I recommend if you're building this computer yourself, that you consult with someone who has built a computer before and also has your best interest in mind. You can explain to them what it is you're looking for. There's a lot of ins and outs of building a custom computer.