Processor Jargon

I am trying to customize and buy an HP laptop but I don't understand what all the numbers mean. All the options are for an Intel Core 2 Duo but the numbers (T6400, T6600, P7450, P8600, P8700, T9550) are so confusing. What does all this mean?

The T6*** are going to be your entry level, basic CPUs with lower amounts of cache and slower FSB speeds. The P7*** and P8*** CPUs are going to be your mid level CPUs and the T9*** are going to be the highend models with the highest cache amounts and FSB speeds.

To give you a general idea:
Basic word processor and web surfing use: the T6400 and T6600 will be fine
Multimedia use, light-medium gaming and heavier office use: the P8600 and P8700
Heavy graphic design, photo editing and gaming: T9***