thinkpad tx20 slice vs dock decision

Hey guys I need help making a decision. I've read a lot about both the dock and the slice (battery issues with sleep, etc... seem to have been fixed) and price is not a concern (I can get both for around $120ish). Here are my thoughts:

Mini dock plus series 3 (90w):
Convenient, no more attaching multiple wires.
Adds more usb ports (I have a lot of usb devices... )
Adds video ports (not terribly important, using vga right now but dvi would be nice)
Comes with ac adaptor, so I can leave one in my bag (although I'm planning on using my 135w adaptor with the dock and using the included 90w adaptor when I am going out.)

9-cell 27++ Slice battery:
I like the looks
I can leave ac adaptor at home.
Currently, I have a 9 cell battery and 7~8 hrs on absolute minimum battery life is marginally enough. I would like to not have to worry so much though

From the way I see it, the dock is a much better deal especially at the same price as the slice, but it doesn't really add any functionality that I NEED - just makes everything super convenient. I just can't get over how 'cool' the slice looks though... always wanted one.

In general, I do take my laptop out with me quite often and I use it for a long time... although most of the time I have access to a power outlet. I would rather not have to worry about whether I have access or not.

I have considered getting both but I don't think it is a good idea... to charge the slice I would either have to buy the external battery charger (don't want to do this) or I would have to take my laptop off the dock, stick my slice on and use the dock's power cable.... which kinda nulls the dock's intended purpose.

Anyone have any input/recommendations for me?