On the Intel side of things, Pentium chipsets perform very well; most of them don't even use dual channel memory, yet stay competitive with the Intel chipsets on range.
Overclocking wise, it really matters on the brand you get. The trick of overclocking nowadays are the quality components on the motherboards, hence brands like ABIT, DFI, ASUS and MSI make out so well.
The last VIA chipset for P4 I had could overclock a 3.0E to 3.4 with no problems at all.