I've not found modular to be _that_ much better than not.... although I went modular on my last upgrade. If I only had £200 though and needed to make some cutbacks then a modular PSU is one thing I'd chuck, it's dead easy hiding PSU cables. Most of the cables end up plugged in anyway - at least for me anyway. You need the GFX card cables, the motherboard cable, at least one 4 pin molex chain and one SATA power chain, by the time all that's in there's not really much that's modular.
The CX600W would serve you well for years, but if you feel you want to go for something beefier then don't go for anything over 700W, it's overkill. Short of more than 2 graphics cards and serious overclocking a 125W CPU you can't use over 700W. JonnyGuru is the best place to read PSU reviews, I'd never buy one without going there or SilentPCReview and reading a review first. No review? No purchase. PSU manufacturers have to send out samples to get reviews done. No reviews means they haven't sent out samples which for me is a good enough reason to avoid em.
The CX600W would serve you well for years, but if you feel you want to go for something beefier then don't go for anything over 700W, it's overkill. Short of more than 2 graphics cards and serious overclocking a 125W CPU you can't use over 700W. JonnyGuru is the best place to read PSU reviews, I'd never buy one without going there or SilentPCReview and reading a review first. No review? No purchase. PSU manufacturers have to send out samples to get reviews done. No reviews means they haven't sent out samples which for me is a good enough reason to avoid em.