I checked recommended builds in gaming magazines, compared them over two months, swapped parts until I was pretty sure it fit my needs. I posted it here for a last sanity check then, and swapped out the PSU after that. Everything else was fine.

Also read tests regularly, and more than once for the same parts. There are some great testing sites out there.

For me the time I took paid off, in the end the PC was perfectly tailored to my needs.

What are you getting bottlenecked by? If it's the GPU (which is most likely) I would just start by replacing that alone. I wouldn't go all new unless you have money to burn.