I use Emacs v. 22 (the console version, either remotely with PuTTY or locally with Konsole) as my primary text editor on Linux. It takes a while to load up each time I start it though, probably almost a second, although I never timed it. I tend to open and close Emacs a lot, because I'm more comfortable using the Bash command-line for file/directory manipulation and compiling.
How can I speed up the start-up time?
Don't close Emacs every time you want to use the shell. Use Ctrl-Z to move Emacs to the background and the fg command in Bash to move it back to the foreground.
One thing that helped me reduce the load time of my .emacs, in addition to autoload (as others have suggested), is eval-after-load. In the following example, delaying the call to sql-set-product saves you from having to load sql in your .emacs, making the exisiting sql autoloads more effective.
(eval-after-load "sql"
'(progn
(sql-set-product 'mysql)
(setq sql-mysql-options '("-C" "-t" "-f" "-n"))
(setq sql-sqlite-program "sqlite3")
))
Of course, for some packages there will be a hook available that you can do the same thing, but sometimes there isn't, or else this way just proves easier to think about.