@qmemo
AbiWord --> I would use OpenOffice + Latex (tetex package)
GnuMeric --> I use OpenOffice, but Gnumeric also should be ok here
Pidgin --> try Gaijm also / I use ekg form IM which is something like centericq
Kazehakase or Firefox or Opera --> As this is OepnBSD you are propably limited to Firefox 3.0, but I would try setting up Opera 9.5
Claws or mutt --> both are ok, depends what you like most, cli or gui
ROX file manager --> I also use thunar (rename feature is great) and nautilus from time to time
xpdf or xview or Adobe acropat --> I use evince here, also for ps files, but I also have xpdf as a backup
xine-ui & mplayer & xmms --> I use mplayer without gui + sonata with mpd, or beep media player if I want fast small media player.
uxterm --> urxvt(rxvt-unicode) is also a great term, bu I used xterm myself for very long also, if you need only iso encoding, then mrxvt is also great
Leafpad --> geany (rocks) or vim (also), check what vim can do btw:
http://vermaden.deviantart.com/art/vim-74228681 but vim can also do text tabs for example:
http://azer-files.googlecode.com/files/vi.jpg I also used mousepad from time to time as on screen notes
Flash Player 9 --> on OpenBSD? Maybe in QEMU wm on windows 2000 / if you just want to dowload videos fro youtube.google video, then use keepvid.com
Bittorrent client --> transmission-cli for simplicity, all you have to do is transmission-cli pr0n.torrent in cli
Xchat IRC --< irssi ftw
K3B or any equivalent --> check my howtos about burndvd and burncd, I used that for burning on BSD
I would also advice feh and gqview for image viewer
galculator for simple GTK2 calk, or well colored xcalc (check mine ~/.Xdefaults :
http://toya.net.pl/~vermaden/text/dot.Xdefaults
Also GIMP + Inkscape for graphics
UAE + DosBOX + WIne for gamez
fbpanel for some lauchbar if you like such things
dunno what else I propably missed something ...