I have just done exactly that using PowerQuest's Drive Image 7 (DI7). Copy facility.
If you choose this too I would recommend the following:-
1. Fit the new drive as slave - jumper instructions with drive and on makers web site -but don't format it.
2. Start DI7, read up "learn about copying discs" then when your ready start;
3. I chose the options for quicker processing (you will see what I mean) but what I think was important was the checking of the box to copy the Master Boot Record (MBR). I didn't do this the first time and ran into problems.
4. When it's all done remove the HDDs and change the jumper on the new one to master and fit it in the appropriate bay. Then boot into the set-up routine to check that the bios recognises the HDD. When it does let the start-up continue.
5. If it all works out, as it did for me today, windows will just come up as normal and you will not see any difference. I heard a difference as the new HDD (Seagate) is so much quieter.
You may wish to note that a couple of contributors to my threads on this subject recommended xxcopy a free download but it looked more complicated to me. I'm happy with this.