nano or IDLE, depending on need.

nano is the best terminal text editor by far, as i don't wanna have to learn a new command line and 2 control modes just to type in ffffffffffucking vim and it's just powerful enough to do what is needed without extra crap on top.

IDLE is super-light-weight, has a somewhat-handy debugger if i need to see what's up when my code interacts with modules or some such, takes up very little RAM and is open-source. Works exactly as needed and no more.