I'm also a speed freak. Here's my take for speed.
Hardware: Intel H61 board, Pentium G620 processor, 8GB Corsair DDR3 1333MHz RAM, Atheros LAN Card, Intel HD 2000 Graphics on the same die of the CPU, 32GB Kingston SATA II SSD as / partition + Western Digital Blue SATA II TB HDD as /home partition.
OS: Debian Squeeze 64Bit, backported 3.2 kernel, mesa, drm and xorg manually backported from Debian Wheezy repository.
Package Repos: Debian squeeze, backports, mozilla-debian, debian-multimedia, google and debian wheeze.
Desktop Environment: Gnome 2.30
Software: LibreOffice 3.5, Gimp 2.6, Mplayer and Totem with all codecs and browser plugins, Iceweasel (Firefox) 13, Icedove (Thunderbird) , Sun Java and Netbeans full suite, GCC + G++ along with Code:Blocks, Full Wine suite, and the fat repertoire of media players, audio/video editors, remote access/desktop sharing tools, mysql server, client and admin, a plethora of games and tons of system utilities and recovery tools.
Speed benchmarks: Booting 8 secs, libreoffice startup 1 sec, firefox 1 sec, gimp startup 2 secs, and surprisingly netbeans startup 3 secs. Initial memory footprint is just 130MB. You can't expect more.
Tweaks I did: Optimized SSD to use trim (noatime,discard option in the /etc/fstab of the ssd drive), disabled ipv6, changed /etc/hosts to look for localhost whenever possible instead of searching and reaching there, removed swap partition, removed initram disk, put all my driver modules directly into the kernel so as to avoid seeking initram. Finally cleaned all the unnecessary locale files, symlinks, orphan files and then a few tweaks on gconf-editor. Finally cleaned the gnome config residues (after installing all the software I needed) with gconf-cleaner.
Here's the testimony video, watch it in HD 720p format full screen: