Intel is known to change sockets and platform approximately every 18 months. But LGA 775 seems to have gone longer than expected. If I'm not making a mistake then, the Pentium4 released in Q4'04 was the first LGA 775 and till date we have the LGA775. To be released next month on 11th November, Intel's new processor-Peryn will also use LGA 775 (may be some extra power requirements). This means that Intel has lasted the LGA 775 for 3 years and that's odd considering Intel's past socket changes.
But Intel's next major change to processor architecture will come in the form of the much-awaited Nehalem line of processors. The Nehalem will be released in Q4 2008 and will use a new socket 1366. That's actually the "number of dots" that connect the processor with the motherboard... The increase in the pin count is actually because of the integrated memory controller. The Integrated Memory Controller from Intel may be a copy of AMD's architecture, but Intel surely will bring lot of enhancements along. Among other things inside Nehalem, Intel also copies a point-to-point interconnect called CSI (now called QuickPath) from AMD (Hypertransport).
Nehalem will also be the first processor to support DDR3 memory and it'll be the first time that the motherboard's northbridge won't decide the memory to be used for an Intel system.
The desktop version of Nehalem will be called "Bloomfield", probably to depict the cash flowers that have bloomed in intel's field. The mobile version "Gilo" and "Becton" for server version... All will be a 45nm fabricated chip and Intel already has a few early samples and has demo'd it to people at IDF a few weeks back.
The Nehalem processor may also be the first native 8-core processor. Integrated GPU may be another reason for the increase in the pin count in Nehalem, but that's another topic altogether. The first generation of Nehalem processors which Intel demo'd at IDF did not have the integrated GPU, so when it releases in Q4 2008 don't expect it to start with an integrated GPU.