I dont use them as much now i am using Fx with the ability to add your own toolbar searches (must try and post these on my website sometime)

2 i still just use from the addressbar are
whois -> http://www-whois.internic.net/cgi/whois?type=domain&whois_nic=%s
ukwhois -> http://cgi.nic.uk/cgi-bin/whois.cgi?query=%s

i also have d,t,g,gg,gi set up for dictionary.com, thesaurus.com,google, googlegroups and googleimages still set up and use them ocasionally

http://www.acronymfinder.com/af-query.asp?String=exact&Acronym=%s&Find=Find
a
(acronym)

http://www.dictionary.com/search?q=%s
d
(dictionary)

http://www.freedb.org/freedb_search.php?words=%s&allfields=NO&fields=artist&fields=title&allcats=YES&grouping=none&x=0&y=0
cd
(cd track listings)

http://www.thesaurus.com/cgi-bin/search?config=roget&words=%s
t
(thesaurus)

/.

http://bugzilla.mozilla.org/show_bug.cgi?id=%s
KW: bug

I probably should set some more up, but I've just never gotten around to it.

Anyway, I should probably get back to working on my BA Paper, which is due tomorrow. :)

Besides my Mozilla-specific techie searches I have:

Google Search
Google Groups Search
Google "I'm feeling lucky" Search
Merriam-Webster Dictionary
Garage/Yard/Moving Sales
hu->en
en->hu

(those latter two translate hungarian to english and back)

There's a (wiki) list at leakytap. These are just the %s kind. For normal boookmarks, I use /. (Slashdot), mzf (MozillaZine Forums) and a few others.

http://www.wormus.com/leakytap/Internet/CustomKeywords

That's a reasonably exhaustive list to share with people.

movie for imdb.com
wiki for wikipedia

I'm an astronomer and use a few for astronomy tasks. The addresses are long, but basically, I have "nedo" do an object search on NED, "adsa" do an author search on ADS, and other things like that. The NED search is especially helpful while observing (if you need a redshift fast).

mail - webmail
staff - manage work website thingy
/. - /.
blogs - http://gemal.dk/mozilla/blogupdates.html (gotta keep the finger your the pulse)
weather - my local weather URL
mz - MozillaZine.org
Moz - mozilla.org
news - the news site I go to often (soon to change)

PHP Manual: php
Google Lucky: gl
Google: g
MySQL Manual: mysql
Merriam-Webster: mw
Google Images: gi
Van Dale (Dutch Dictionary): vd

I'm positively addicted to the g one, I have iton every browser I get to use regularly, and if it doesn't work I'm severely crippled.

mz - mozillazine.org
moz - mozilla.org
news - newsforge
sf - sourceforge.net/projects/%s
bz - bugzilla
map - streetmap.co.uk (with %s for postcode)
train - nationalrail.co.uk
weather - onlineweather.com
jedit - jedit.org
jdk - local copy of Java Api

Probably some others that I use so infrequently that I forget what they are!

Amazon UK: amazon
Ebay UK: ebay
IMDB search: film
MultiMap UK: map
Wikipedia: wiki
First Bus (Glasgow) bus numbers (for any other Glaswegians out there :o) ): bus

bug - bugzilla.mozilla.org (as in aebrahim's comment)

kb - http://support.microsoft.com/default.aspx?scid=kb;en-us;%s

tid - http://support.novell.com/cgi-bin/search/searchtid.cgi?/%s.htm

The only two I regularly use (besides "bug" for Mozilla bugs) are for webcomics:

mt for Modern Tales comics

gs for GraphicSmash comics

So if I want to check the latest installment of Rogues of Clwyd-Rhan, I type "mt rogues". If I want to see the latest Killroy & Tina, it's "gs killroyandtina".

Mapquest map and Mapquest directions are my two favorites, I also use imdb, three for lxr.mozilla.org (text, filename, identifier) and RFCs. I probably have a handful of others around as well.

My map bookmark handles entries like this:

map [street-address,] city, state

Where the street-address is optional, and directions works similarly:

directions [source-street-address,] city, state to [destination-street-address,] city, state

You can find them both on the bookmarklets page of my website:

http://segment7.net/projects/web/bookmarklets.html

Keyword searches:

imdb
bm (takes me to my del.icio.us bookmarks that match the http://del.icio.us/username/%s )
lj
xanga
amazon

In my previous company I had one for:

phone , which was hooked up to our corporate phonebook.

I have a whole bunch of bookmarklets I can't live without. I uploaded them to http://jan.moesen.nu/code/browser/bookmarks/. Hope they are of use to you too.

Whoops, should have used HTML: Jan!'s bookmarklets

the only custom keyword i use a lot is for stock quotes

q NOVL
q RHAT
q SBUX

1822 - https://www.1822direkt.com/
acr - acronym finder
asta - http://www.asta-bonn.de/
block - List of bugs blocking 1.7
blog - http://www.blogger.com/
branch - bonsai query for checkins on MOZILLA_1_7_BRANCH in the last 24 hours
bz - Bugzilla
ct - http://www.heise.de/ct/
dict - http://dict.uni-leipzig.de/index.php?wort=%s
ebay - http://www.ebay.de/
gmx - http://www.gmx.net/
gmxs - https://www.gmx.net/
heise - http://www.heise.de/newsticker/
hot - http://www.hotornot.com/
last - bonsai query for checkins in the last 24 hours
leo - http://dict.leo.org/?search=%s
moz - Mozilla
mz - mozillazine
n - new bug reports added today
taz - http://www.taz.de/
typo3 - http://www.asta-bonn.de/typo3/ (CMS login)
wp - (German) Wikipedia
wpen - (English) Wikipedia

perlfunc: http://www.perldoc.com/perl5.8.0/pod/func/%s.html