Yep. I agree that you should get the largest case you can. I went for the Cooler Master ATCS 840.
It is huge and made of solid aluminium. All the construction is tool less and the motherboard tray slides out on roller bearings. It can be taken out completely so you can build your pc, mount the mobo, chip etc. outside of the case, on a horizontal surface, and then slide it in. Similarly there is an access from the other side of the mobo tray so large HSFs can be easily mounted.
With this case I can upgrade in any way I want to. Large GPUs are no problem, plenty of space for water cooling if I want it, plenty of room for more drives etc.
Having worked on other cases and spent ages bent over trying to fix things I can barely see or reach this was a dream. Likewise cable management behind the mobo tray makes for better air flow.
Admittedly this case and others like it (Corsair Obsidian?) carry a high price and it's up to you if you want to spend that much on a case but the general principle of having plenty of room can also be applied to the more budget cases.
Basically it's worth doing quite a bit of research on this. I managed to find video reviews of the case and a video tutorial of an actual bulid with it!
Good luck, John