Last gen;
Resident Evil 4
Final Fantasy XII
Tekken 5
Killzone
Ratchet & Clank
Jak & Daxter

This gen (so far);
Resistance: Fall of Man
Killzone 2
Heavenly Sword
Uncharted 1 & 2
Folklore
Little Big Planet
In fact....I'd rather have the Playstation 3 itself...just there....than any of the games from the last generation....

There's a few multi titles I like from this gen...Bioshock,Resi5.....but my Playstation fanboyism has gone into overdrive in the past three years,and I find I'd rather play Lair 24/7 than consider listing any multi.
It really is that bad with me....I worry sometimes.
Gears is....nice.

Its not hard to pick my most memorable game last gen. Dragon Quest VIII.

Considering I spent 168 hours on it, and then played it again, I'd consider that pretty memorable.  But playtime alone didn't make it memorable, as I can say the same thing for Suikoden III, Capcom vs SNK 2 or Grand Theft Auto: Vice City.  Mostly I'd just give it the title because of the actual game content which gives you that combination of 'epic' and nostalgia feeling, which few games last gen did for me. I can freely admit that there were many good games last gen, but this one even before I was finished with it became one of my all-time favorite games and I knew I would have fond memories of. Something on the level of a Ocarina of Time, Tie Fighter or Diablo II.

As of yet this gen, no real game has come close to the powerful combination Dragon Quest VIII gave me. Though I can say this gen has probably produced more 'classic' games for me than last gen such as Kirby's Canvas Curse, Osu! Tatakae! Ouendan!, Smash Bros Brawl, Super Mario Galaxy, Muramasa: The Demon Blade and Dragon Quest V DS. But as of yet, I still am looking for that absolute gem that I can call the 'one'. Perhaps it'll be Metroid Other M or Dragon Quest IX.  Or possibly Diablo III or Star Wars: The Old Republic, though those are going to be on PC.

dont understand why people say RE4 was so memeriable
RE1, 2 and 3 are way better

love RE1 for the gamecube!

Halo 2 was my favorite game last gen. No game has yet surpassed it but both gears of war and halo 3 have come close...

Most memorable? Has to be Killer 7. That game is so weird, it'd be hard to forget.

First off it's game play is so different... then well everything is so bizaree.

If i have to chose one, i will go with MGS2

And yes i favor MGS4 a little more than MGS2

Hmm. Mine would probably be Smash Bros. Melee. Me and my friends played that game to bits. So many hours, ah, probably into the quadruple digits... Brawl is better, though I'm not playing it nearly as much.

Also, Wind Waker, fabulous. And I think TP is superior, although I prefer WW's style.

I'd say FFX was my favorite last gen.. no games this gen is even close, hell not even close to my top 5 last gen. But got high expectations for 2010 :P

While at university, I didn't played videogames, so I jumped from my N64 and PSX to Wii and PS3. Nevertheless, I'm having a great time enjoying games of the GC and PS2 nowadays.

From last generation, what I've played and loved so far has been:

Tales of Symphonia
Persona 4
Zelda Windwaker

From this generation, the games that I am sure will be remembered are, so far:

Uncharted 1 and 2
Fire Emblem
NMH
Mario Galaxy
Punch Out!!
HotD: Overkill
Valkyria Chronicles

Then, specially with Nintendo consoles, you have lots of wonderful games that are available for both:
Zelda: TP
Metroid Prime 1 and 2
Resident Evil 4
Donkey Kong Jungle Beat
Pikmin 1 and 2