Kyocera Slider, Blackjack, and LG NV were my latest cell-phone wise, though I've done a lot more flashing with stuff for Gameboy Advance and DSLite (esp for running 8-bit classic ROMs). GBA stuff used to be annoying to flash, so much easier with some of the SD carts that are available now though.
I got thoroughly disgusted with smartphones after my Blackjack (crappy reception), though I thought my work Blackberry was decent (no crazy mods to that though, obviously, just some tethering fun).
I've been pining for an android phone since they came out (so much easier to tinker with!), so glad I'm finally getting close to renewal.
I strongly believe in - if I bought the device and it's mine, and I don't hurt anything, why can't I see what it can do?