I run 60 steady. Full settings on just about everything. i think it's capped though, not sure. I haven't really toyed around with my card or steam. to see if i can get more.
I'm pretty sure DVI doesn't have anything to do with frames per second. It is simply an interface standard between the graphics card and monitor. It can effect the quality of the video, but not the speed at which frames are generated by the computer.
You'd want a graphics card, CPU, or memory upgrade to help with FPS. Sometimes disk speed can be a bottleneck, but it depends on the game/map/etc. The 8800GT line is coming way down in price and a good option if you already have a PCI-E motherboard.
To answer the original question, I get 60+ when there's little or no action, and it can dip lower than that (say 30 or lower) depending on the situation. I don't run at max settings or anything, although I did just do a graphics card update recently.
You probably wouldn't want more than 60 fps, at least if you have an LCD. They generally refresh at 60 Hz, so any more generated frames per second would probably be wasted.
I get around 55 fps average with drops too about 25 but no lower than 25 during heavy firefights. I play windowed at a low resolution, with all settings set to high. Not bad for my 2 year old PC i'd say. I think i payed around $95 american for my gfx card back then.
My framerate seems to vary from the high 20's to 70's regardless of what settings I am using. I think this is due to me having a fairly fast video card (8800 GTS) and a fairly slow CPU (1.8 ghz dual core). Unfortunately TF2 doesn't make full use of multiple core processors. I read somewhere that the second core is only used for particle effects.
7g, you are probably are not running all settings maxed out.
With all settings maxed, on UXGA, I get 100fps on an empty server, 60 in most of goldrush or blackmesa, and maybe 30 in really crowded areas. It seems like less than that though due to lag/latency/packet loss.
Well I figured he wasn't running it maxed. The thread didn't say to state what settings you had, it was just optional. I included my settings because I wanted to .