How do I block the websites that kill all my time?

http://kb.mozillazine.org/Parental_controls

What I did when I had the *same* problem was to set up a squid proxy on my home system so that I could create the necessary permissions there. I blocked "evil" sites between 8am and 12pm, then from 1-5pm just like at a corporate network. Because this was on a separate system, I even configured my home firewall (Linux/iptables) to deny outbound HTTP from my laptop during those hours (meaning I HAD to go through the proxy to do ANY surfing at all). It worked like a charm: do actually do some surfing I had to either go into squid to disable the policy OR change my ipfilter rules. I eventually grew out of it (thanks David Allen & GTD, along with 43 Folders and Lifehacker!) but this was very useful for a while...

Temptation Blocker sounds good, but I need something that blocks sites within a browser, not the browser itself -- and I need it to be non-trivial to disengage, so something like parental controls or a basic Greasemonkey script won't do the trick. If it's easy to just turn it off and relapse, I will...

Block their IPs in the firewall.

Well, why don't you get a friend to set the (Mozilla equivalent) supervisor password for your browser, and get them to disapprove certain sites. That way, it is non-trivial to disengage on a day-to-day basis but entirely reversible (if your friend is non-evil).

You can edit your /etc/hosts file to block individual sites (just add a line for each domain name you want to block, e.g.: 127.0.0.1 foo.com) You can still disengage it by removing the line from /etc/hosts and waiting for the DNS to update itself, so it's not a lot of hoops to jump through, but it's a start.

I too use FF and luv all the exts but it is murder trying to locate anything through their site, you're right. What I do: I don't blindly surf. I use Bloglines to give me daily updates from sites that I tell it I want to be kept up to speed on which is done on a daily basis (actually every few minutes most of the time) via each sites RSS feed (you may have seen the little orange buttons). There are other sites but BlogLines is the most popular and since it is a website, it can be accessed from any browser while online, unlike apps that you can download that do the same thing but then you have to be at home to read from your daily list (although you could obviously go to each site manually but then you are wasting time seeing whether or not there is anything new, why bother when you can just get an online version?) With this setup, I never surf blindy (who has time for that?) and am getting only info from sites that I know (so 99% no malware). From time to time, I actually go to their site (because normally you will just be reading everything thru the Bloglines website) and it is then that I see other site links that I may want to visit (for possibly subscribing to also). FYI: I am subscribed to the FF site for new exts too so I see them as soon as they are added to their DB, no more searching for me! One more thing, you may want to go further and look into OPML where you can share your reading List with others, or at least search thru other people's OPMLs to get an already put together list (that you could of course tweak by subscribing to only some of the sdame links as what they did). There really is so much to go over, look thru my http://del.icio.us/BillyG/OPML or http://del.icio.us/BillyG/RSS folders and maybe that will help some more. G/L.

It's an idea, but it'll never work. If you want to stop one time-wasting behavior, you have to replace it with another, hopefully less wasteful, behavior.