Most likely the "high end" sandybridge chips will be out by then. These cpus will require a different socket which is known as lga 2011 and will have 2011 pins.

That said the successor to sandybridge called ivybridge can be out as soon as h2 of 2011. Ivybridge will be a dieshrink of Sandybridge the same architecture, in other words the same or similar hardware but running much cooler and maybe with higher frequencies. Who knows if ivybridge will have lga 2011 varieties in h2 of 2011 or if you will have to wait.

To get an idea of how small Ivybridge is, if they keep the current cpu that Blackadder bought, made no changes to it, it would physically be 1/4 the size of the cpu that Blackadder just bought.