As a general rule...Ready to stand for my words, but here you have it :
Mobile Chips S__xs ! The perf beetween a mobile chip and a non mobile is amazing. My sager ( p4 2.4 non mobile ABSOLUTELY KILLS an Dell Latitude p4 2.4 Mobility desktop replacement , like by several second every where). Remember mobile have a 400 Mhz FSB only vs 533 / 800 for non mobile chips.
If ya don't care about heat, portability and bettery life and want ABSOLUTE performance, go for a full blown 478 pins Non Mobile P4 CPU.