Rxvt, normally on Cygwin. If I had more use for Unicode in practice, I'd use urxvt on non-Cygwin.
Also, when ssh into remote boxes, I often use screen, which effectively ends up being a pretty crappy terminal - major failure mode is loss of scrollback buffer, Ctrl-A ESC notwithstanding.
Mouse wheel / Shift+PgUp is infinitely more usable for scrollback access than Ctrl-A ESC. Ctrl-A ESC is sufficiently hard to access that it might as well not be a feature - rather than scroll up to see a command's output, I re-run it piped to less.
Try Ctrl-A + [ which puts you into 'copy mode' and ] to exit 'copy mode'. While in copy mode you can use arrow keys and/or page up/down to go through screen's scrollback buffer.
I usually run anything that will have a wall of text piped to less anyways (with or without screen).
Also, when ssh into remote boxes, I often use screen, which effectively ends up being a pretty crappy terminal - major failure mode is loss of scrollback buffer, Ctrl-A ESC notwithstanding.