PC - this is more of an ensemble effort by a few companies (mainly AMD and Valve for me). First of all, the prices have been astounding. I built this PC two years ago for a mere £450, including 1.5tb of HDD space and a Blu-ray drive. I expect it could stay relevant for as long as another two years.
Then there is Steam, such an incredible service which makes PC gaming what it is imo. Along with excellent social features, it has given me massive savings through its sales - none of this 10% off nonsense like other crappy sales, i'm talking packs of 40 games for £50. It's how digital distribution must be done, so take note XBLA and PSN.
Then there are the obvious graphical advantages of PC like native 1080p, which the consoles disappointed me with their lack of, as well as adjustable levels of AA and AF that vanquish eye-gouging jaggies and blurry textures. Performance woes also disappear as most games I own run at 60fps. Emulation ties in with graphical advantages, as I can finally play my PS1 and PS2 games without the horrible blurry upscaling. The mod scene is also continually improving games like GTA4, Dirt 3, Fallout, Crysis, Doom 3 etc. not only visually, but also in how they play.
Finally, the ability to have a choice between keyboard controls, a PS3 controller or a 360 controller, as well as flight sticks, wheels and arcade sticks, has been most welcome. All genres can be enjoyed to the best of their abilities without some annoying niggle holding you back.
PSP - i've been a supporter of the PSP ever since Dark_Alex released the PS1 emulator in 2006. From that moment on I had to own one, so I sold my DS and bought a slim model in late 2007, hacked it and unleashed handheld perfection.
It still thrills me today to be able to play the games I grew up on like Metal Gear Solid, Resident Evil and Final Fantasy VIII on the move. I don't think i'll ever truly get over how awesome that feeling is. Emulation also allowed me to play all my old GBA games like Pokemon on a larger screen with a proper backlight.
Old games aside, PSP games were great as well. It's become the go-to console for JRPGs in recent times. It's home to stacks of smaller titles with interesting little hooks like Patapon, Lumines, Badman, and Patchwork Heroes. Square Enix support has been pretty godly (although i'd like to see some of that sugar on other platforms too). And it's had a few massive successes like Peace Walker and Monster Hunter Portable. Ultimately it's a 'quantity' console, made up of a large amount of great games rather than a few jaw-dropping ones.
Until I got a smartphone, I also used it as my primary music and movie player. Once you got passed the format limitations and had custom firmware, the unit was pretty capable.
It all got even better in 2010 though. Sony had released the Go, a better model all round - I was impressed at the flawless screen, pause game functionality, Dual Shock 3 support, video out, the more comfy form factor and the on-board storage. When it got hacked, I immediately bought one (kept my slim too for UMD ripping). I slapped an additional 16gb memory stick in there for a cool 32gb of total space, and the rest is history. PSP Go is the best handheld ever made, so thanks Sony for it and the games, and thanks hackers for making it worthwhile.
I hope Vita follows the same path.