TI-89 Titanium or an e-book reader?

I can get one or the other for Christmas. On one hand, I can use the TI-89 Titanium for all my calculatory needs. On the other hand, I can read all about computers using an e-book reader.

Why hasn't anyone made a programmable e-book reader/graphing calculator?

Grr. What should I get?

... or maybe sod them both and get a Sega Mega CD II?

Get an ebook reader. And then get Wolfram Mathematica and forget about that TI-89.