Can't agree more. I had a M100 with Keyboard and since switching to the M500, I miss the board alot. I have a laptop for updating the Palm Desktop but unless you buy the Desktop version of products like Thought Manager you miss out on the speed possible with the Keyboard. Now to save up the $150 Canadian to buy it.
A small aside - Thought Manager looks good for managing lists so far (have it, bought it, love it).