For more than 32 port pins I would look a really hard at some of the derivatives in bigger packages. There are plenty of them available. It is not uncommon when you consider extra part costs, extra PC board space, extra place and installation costs and debug costs that adding extra parts to a design can be more expensive than using a derivative with more pins!!! This is a fact over looked by many engineers that only look at the cost comparison of the processors by themselves in 1->10 quantity. Also if you consider that these modern day parts with more pins are in smaller packages and operate at 3.3 volts these parts also fit in better with many other modern day projects, peripheral components, and device packaging as well.

For instance, look at the COG graphics displays I have been messing around with (Graphics Project). These displays typically operate at 3.3 volts and fit very nicely with 3.3 volt processors.

I also have to beg to differ with those that argue that these modern day surface mount processors are hard to prototype with. I have found that the methods in this article on High Density Processor Prototyping are very effective and I have used them quite a few times.

Michael Karas