FF: I either use the drop down in the address bar OR click in the address bar and type H and hit down-arrow then enter OR click on HN image in speed-dial OR if I'm feeling keyboardy I use ctrl+L to get to the address bar then type H and hit down-arrow, enter.
I type "news." in Chrome or firefox and select "news.ycombinator.com"
I type "n <Down> <Enter>" in Firefox's Awesomebar. It's like Googling for sites you visit frequently, but with a local database optimized just for me.
Speed dial on Opera, pinned to the 'new tab' page in Chrome. Sometimes I start typing "news." which is autocompleted accordingly.
Ctrl-l, n, enter
I have the new-page within my first 8 ff tabs at all times, so I can always hit Alt-number-f5.
I just press n <TAB> in the address bar in Firefox or n <ENTER> in Chrome.
Often just select the icon from the home screen of my iPhone...
Command+3. It's the third shortcut in my Safari toolbar.
Ctrl+Space Y. Site Launcher extension for Firefox.