My suggestions for nice (but by no means necessary) lighter software for older systems are Sylpheed or Claws for email and for SOME (but not all) of your browsing, you might not need all the features of Abrowser and prefer something lighter. Midori is included on Trisquel-Mini, but Dillo is also quite nice and if you leave the defaults alone, it just won't do what you want on sites where you're better off with the added security of Abrowser.
You will want to install Greasemonkey and a YouTube HTML5 script on Abrowser instead of the Flash software you used on XP if you use You Tube. Don't dismiss text browsers as too dated or too geeky--eLinks is quite modern and it's easy on the mind and the eyes to take a break from all the flashing banners and unnecessary pictures of cats once in awhile and just focus on the actual content. Kudos to you for keeping the old gal out of the landfill and doing so safely.
