So, once you decide upon a list of websites that you would like to speed dial, open the 'Organize Bookmarks' link by holding Ctrl+Shift+O else open it via. the Bookmarks tab.
Select 'New bookmark'. A screenshot is attached, where-in I have added the HDFC bank login with the keyword 'HDFC'. Note that the keywords are case-insensitive. So, even if I type 'hdfc' instead of 'HDFC' (note the case), firefox would open-up the login for HDFC bank. Even though this is a simple technique, not many are aware of this. The good thing is you can even have numbers as a keyword for a website.
If you decide to export your bookmarks to another browser, say 'Google Chrome' for example, you would not lose out on this feature. I haven't tried it on Safari or Internet Explorer so far. Tell me if it works for you!