I haven’t put much effort into finding blogs to follow, but I like these.
http://toiletwolf.tumblr.com/ (Unusual, original photography with impeccable composition)
http://firebirdman.tumblr.com/ (Original photos of interesting cars found on the street)
http://thechrisgethardshow.tumblr.com/ (Blog of my favorite TV show)
http://9eyes.tumblr.com/ (Google Streetview images, updated only occasionally)
http://nickgerber.tumblr.com/ (Original architectural photography)
http://humansofnewyork.tumblr.com/ (of course)