I like terminator. It's very lightweight, and comes with lots of features that make it a unique terminal program. My favorites include horizontal scrolling (as opposed to the default wrapping behavior in most terminals), smart autoscroll, built-in finding capabilities, but the end-all feature (for me) is the window-splitting capabilities. If you're familiar with splitting windows in emacs, it's very similar.
Here's an excerpt from the site and some of the better features:
Terminator is a cross-platform GPL terminal emulator with advanced features not yet found elsewhere.
Terminator will run on any modern OS with Java 6 or later. It replaces xterm, rxvt, xwsh and friends on X11 systems, GNOME Terminal, KDE's Konsole, Apple's Terminal.app, and PuTTY on MS Windows.
I suppose I wasn't necessarily referring to memory usage/startup time/what have you when I said lightweight, but I definitely see how that might be implied. There's no doubt that using the JVM adds weight to an application in these terms. Given that, I still say it's a relatively lightweight terminal, especially considering it's running with Java 6+.
I admit my faux pas, however, and offer the following results to make up for it. :) I tried to do two things: give the terminal a load (printing ~7000 lines from /etc) and test its startup time. The latter wasn't possible in a couple of the programs I tested (unless someone knows a trick I don't). The others were tested using
time and are simply told to exit. For example,
time rxvt-unicode -e 'exit'.
ls $(find /etc) startup time
rxvt-unicode real 0m0.100s real 0m0.045s
gnome-terminal real 0m0.368s real 0m0.215s
terminator real 0m0.366s real 0m0.490s
xfterm4 real 0m0.365s real 0m0.021s
xterm real 0m0.090s
xvt real 0m0.163s real 0m0.007s
guake real 0m0.496s
aterm real 0m0.092s real 0m0.025s
Each result is the average of three trials. You can see, the JVM really bogs terminator down in terms of startup time (expected), but I was surprised to see it perform on par with the likes of xfterm4 and gnome-terminal for the first test.
Please feel free to expand on this.