I'm liking the look of 4e familiars. It also looks like the xorn and the djinn will be making a comeback in MM2.

As well as Familiar stuff for Arcane Power. Wow, unlimited range for the cat. That be useful.
I want to see a snake next. The cat and snake have been my two favourites for mundane familiars. I am glad got a acrobatic/stealthy familiar, my Rogue/Warlock will be happy.I love, love, love the fact that the very first examples we're given include what is essentially an imp or quasit, as well as a mundane option like a cat.I'm hoping for a lot more of that sort of thing.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.