Difference between Intel Core Duo and Intel Core 2 Duo

It's basically just a big speed boost in performance

On some cases, Core 2 Duo proved to be on average 30% faster than Core Duo alone, which is pretty huge

There's no such thing as a 2.4 GHz Core Duo. 2.4 only came as Core 2 Duo, not Core Duo. November of last year (2007 I'm assuming) had Core 2 Duo's all across the line. Core Duo machines were discontinued somewhere towards the end of 2006.

The new processors out now have a slightly faster front side bus but a little less L2 cache. No huge difference whatsoever IMO.

Only the original Intel machines came with Core Duo processors. The principal difference is that Core Duos are 32-bit and Core 2 Duos are 64-bit processors. There were also increases in available clock speed, L2 cache, and frontside bus speed. The first models only addressed 2 GBs of RAM. Later models had a different memory controller that enabled 3 GBs of user accessible RAM (4 GBs installed) and even later models such as yours had a memory controller that enabled accessing 4 GBs of RAM (4 GBs installed.)

The first Intel Minis came with a Core Solo processor which had only one core instead of two.

...but a little less L2 cache

Not actually an accurate statement as it depends on which MB Pro you go for as the 2.4GHz model has 3MB L2, but the 2.5GHz and 2.6GHz have a whopping 6MB L2! Previous generations L2 are: MacBook Pro Late 2007 4MB, MacBook Pro Mid 2007 4 MB, MacBook Pro 2006 2MB. The higher end Penryn's are a significant boost for the MB Pro in many respects.