So I have a machine that I have been running with two Nvidia GeForce 8800 GT video cards for two years now. Been running fine but now I am starting to notice that some games are requiring more performance to run at the quality levels I have grown used to. I originally got the 8800 GT's because they had decent performance for single width cards, and I didn't like the idea of having to sacrifice two PCIe slots for just one card, and have benefited from the modularity when I've been in a bind and had to add either additional networking cards, sound cards, and/or RAID cards. But looking through the available video cards of both ATI's and Nvidia's most recent series, it seems like the quality of single-width cards has decreased a lot and almost every card now has to be double-width for the cooler.
So my question is if I am a user who likes his modularity, but also wants to improve his graphics performance, should I stick to lower-quality single width cards or should I just invest in dual-gpu cards to allow me to justify taking up two slots by having a card with dual-GPU's?