This suggestion should be filed under "usability improvement".
I do a lot of searching (like *everyone* should) and find it very, very annoying that I have to click the main search button and then pick the forum from the long, long list. It would be much faster if I'm currently in the Impulse forum and press Search if it would open the standard search screen but with Impulse preselected in the listbox. Seriously, it would shave at least 3.742 seconds off each of my searches.
This is primarly annoying because I'm a keyboard man. Back in the old days before there was a billion forums the listbox was sorted alphabetically. I could tab to the listbox and press "I" repeatedly until Impulse showed up. Now the listbox has all of the items prepended with dashes and what not making it impossible to use the keyboard to easily pick from the list.
Ideally the main Search button would just magically pass the forum identifier and preselect that forum in the list. If I'm not in a specific forum the Search screen would look like it currently does. It would also be acceptable to have a specific link/button in the forum (like the subscribe to forum/mark forum read links).