If you're still typing out an entire base URL, simply type the name into the address bar (philb for example) and then press Control and Enter. This will pop the www. and .com in for you.
Looking for music to listen to? Go to Google and type Type -inurl:(htm|html|php) intitle:”index of” +”last modified” +”parent directory” +description +size +(wma|mp3) “name of band or artist” (Do of course check that you're legally entitled to listen to it, obviously.)
Do a reverse image search in Chrome by holding down the S key and doing a right mouse click over the image that interests you.
Control-shift-T will reopen the last closed tab in your browser.
If you're in Chrome and want to highlight the URL, Control-L will highlight it for you.
Want to get to the Windows Task Manager a bit more quickly than the Control-Alt-Del approach? Control-Shift-Escape brings it right up for you.
Looking for something on a webpage and can't find it? Control-F to bring up a dialogue box which allows you to search.
What are your favourites? Add them in the comments!