Choosing Laptop Processors - Core Series

Intel processors have been among the most confusing lines of CPUs yet, since they feature completely different naming schemes compared to the hardware on Desktop CPUs. For instance:

Core i5 760  in desktop: 2.8GHz, 3.33GHz Turbo, 4 cores, no HyperThreading

Core i5 450M in laptops: 2.4GHz, 2.66GHz Turbo, 2 cores, HyperThreading

So, it should come as no surprise that the desktop CPU is more than two times faster. HyperThreading helps a bit but not enough to really turn a laptop into a power machine. General rule of thumb, if you get a desktop nowadays, you get twice the CPU performance for slightly less money -  always go for quad cores, i5 700+ and i7 800+.
Still, even in laptops Intel doesn't make it clear what they're selling to the customers, so I'll try to be of some help here. This is what I've been able to gather.

• Intel Core i3       - 4 threads, 2 cores
• Intel Core i5       - 4 threads, 2 cores, Turbo
• Intel Core i7 non-Q - 4 threads, 2 cores, Turbo, +1MB L3 cache(4MB), Hardware AES, VT-d, TXT
• Intel Core i7 Q     - 8 threads, 4 cores, low clocks, 6MB L3 cache on 700 models, 8MB on 800 models

Intel Core i3/i5/i7 U series have the same hardware as the other processors but lower base clock and power consumption. A Core i3-380UM is much slower than a Core i3-380M since it runs at 1.33GHz vs 2.53GHz base clock and there's no Turbo.

The Core i7 Q processors are not very fast compared to Core i7s 600 with higher clocks(the 640M is basically the same speed as the 720QM in heavy load) since they run at speeds not higher than 2GHz in base clock. In my book this makes the Core i7-600 a better choice for high performance mobile processors.

The Core i3s are the best choice all around, with a special mention to Core i5s only if you use a lot of virtualization software since some already allow VT-d to be used, providing better graphics performance in guest operating systems by allowing virtualized access to the GPU. The Core i3 still supports VT-x, which means it will still be very fast at the rest. The lack of Turbo isn't particularly problematic since most software is already threaded to some degree and in those situations the use of Turbo will be limited and i3s and i5s clocked at the same base speed will converge to a similar performance.

If you need help deciding do drop by the forums and I'll be sure to help you look at some options.