Dear lazyweb: To i7 or not to i7?

So, my home laptop is finally on its last legs. I'm sure a full reinstall would help, but to be honest now that I'm playing with WebGL and now OpenCL (a new standard for number-crunching using graphics cards, which sounds like it has interesting Resolver One possibilities) has appeared, a Centrino Pentium M at 1.6Ghz and a crappy Intel graphics card really won't cut the mustard. Add on to that the fact that I'm dropping my home desktop machine and becoming a laptop-only person, and it's really time to change.

The most tempting lappy out there for me is the Dell Studio XPS 16, which is extremely high-specced, has a very well-reviewed screen, and has what looks to me like an underpriced SSD upgrade (£240 upgrades you from a 500GB 7,200rpm drive to a 256GB SSD). The only downside I've noted is that apparently they run quite hot, but so long as I keep it on the arm of my armchair or on the desk, the risks should be minimal.

My big question is, though, which processor? I don't want a fully-loaded system (largely because I can't afford it) so the choice appears to be between a Core 2 Duo T9600 (2.80Ghz, 1066MHz FSB, 6MB cache) or a i7 720QM (1.60Ghz, 1333MHz FSB, 6MB cache). They're pretty much the same price. The i7, when running single-threaded code, overclocks itself using Intel's "Turbo Boost" and runs at 2.8Ghz anyway. And the benchmarks are better for the i7, so while it's hard to work out what's likely to be best for my ultimate usage patterns, the i7 looks most likely to win out speedwise. OTOH it consumes more power, which means that (a) battery life will be worse and (b) the heat problems that people have mentioned will be worse. And I'd rather not have a laptop that turns into a small puddle of silicon while I'm using it, bringing the Thomas line to a premature close -- or that, alternatively, makes a noise like a jet fighter taking off every time I run something computationally non-trivial.

Sadly, googling for comparisons between the CPUs (even after filtering out all the spammy "shopping comparison sites") didn't really lead to anything useful to help me make a decision. So, does anyone reading here have any ideas?

(UPDATE I got the i7)