I have two options fo ron the go. Depending on how heavy I travel these are: Thinkpad T61 or Packard Bell dot-s netbook.
Both run archlinux with i3 as window manager so I usually don't really notice perforamnce issues on the netbook.
For an editor I was always a fan of vim but I recommend using what you are comfortable with. IDEs like Eclipse are nice but if performance is at a premium I recommend jsut sticking to an editor and a shell.
saw the talk at fosdem yesterday. would be happier if they would have tried to be just a mail user agent instead of their vision of being everything at once.
Well but maybe hte unix philosophy of doing one thing really well really is dead