Custom built is not for everyone. Researching hardware can be a time consuming and daunting task for anyone.
I would suggest buying from a smaller shop. You will get better hardware and, most of all, much better support. You still need to be aware of hardware. Main thing is not to scrimp on the motherboard.
I put a list of hardware together when I needed another machine. I found a machine on Ebay with the hardware I wanted. It was much cheaper than I could have bought the parts for. It is well over a year old now and bullet proof.
www.motherboards.org