It took me a LOOONG time to give up my 8100, went through 4. I finally upgraded when the 9700 came out, but I still have all my pearls, IMO nothing beats how fast the suretype keyboard is, the PERFECT compromise between querty and a 'normal' keyboard.
The size also holds a special place in my heart, I couldn't believe people going for the iPhone when it came out, that thing was (and still is really) HUGE. The pearl was really feature rich for its size/time. I almost waited for the 9100.
And lastly, know sometimes it would get stuck, but I miss the feel of the trackball...