Linux still has lots of problems with suspend/hibernate/resume on laptops (Oneiric broke hiberanate on my laptop for example), so booting is still kind of important for that reason.
Resume from hibernate is another area where I'd like to see improvements. I hibernate instead of suspend because I never know if I'll make it back to an outlet in time.
It's more of a problem with hardware more interested in coding to "works on Windows" than "complies with spec."
And honestly, Startup is as fast as resume these days - the problem is applications that don't remember last known state and window managers that won't remember the rest. Why don't we fix that instead rather than chasing down all the suspend bugs?
Restoring app last state? Like terminal emulator recreating tmux session wrapping screen session with package manager working under sudo? SSH unHUP-ing processes on remote machine? Python VM resuming all scripts in a precise place and state they were stopped?
The problem is that there is no such thing as isolated "application" on Linux or any other real OS.
I've had some problems with Intel graphics on my DELL in Fedora 14. Sometimes video, sometimes full screen flash, and sometimes sleep caused it to crash. On my older IBM with ATI, everything worked just fine. Anyway, in Fedora 16 the graphics and sleep works just fine for me.
I definitely could be wrong in my conjecture. I've used sleep reliably under Arch Linux in the past. (Not using it now because my laptop doesn't work anymore without being plugged in.)
On the same hardware that Ubuntu (and friends) didn't work on? I've been having problems with resuming, and wondered if going to Arch would help, but couldn't think of a real reason why it would.
It's not a fair test; haven't tried a recent Ubuntu, but: suspend to ram and suspend to disk were broken on Ubuntu 10.04 and 10.10 with my Eeepc 900. Arch + TuxOnIce has worked great for suspend to disk for about a year now.
Resume from hibernate is another area where I'd like to see improvements. I hibernate instead of suspend because I never know if I'll make it back to an outlet in time.