imo, slackware is for hobbyist who like to spend their time at the keyboard. but if you like that, then maybe that's a good option for you.
there's a decent (but very limited) review of some lightweight distros here : http://www.linux.org/dist/reviews/lightwt_linux.html
to increase boot speed:
use a 2.4 kernel
don't use a graphical interface
however, hibernate and wake-on-lan may be issues and is as much hardware-dependent as it is OS dependent. and you may need to use a 2.6 kernel for that. I haven't had a lot of success with acpi under linux.
sorry, nothing definitive, just some thinking out loud...