Well as the addege does; if it works, don't fix it!
The shuffle is the only iPod that hasn't been updated in a while really - and besides which, it is very functional, and surely the only reason they would update it is to give the line a bit of a refresh and hence some more advertisements and free press.
I think a lot of us MR folks are very appreciative of the fact that Macs are once again getting some limelight! You will have your updates but i can't see it happening before the summer season kicks in...maybe June/July...who knows!
Shuffle will hold it's value (in terms of what you pay for it!) Get the 512, it'l hold loads of songs for you, is durable and reliable and you just can't go wrong!