Good thing you only need to name 5 then...

top 20:

Yoshi's Island
Paper Mario
Gameboy Camera
Animal Crossing
Animal Crossing: Wild World
Elite beat agents
Legend of Zelda: Twilight Princess
Mario and Luigi: Superstar saga
Super Mario World
Sonic the hedgehog 2
Pokemon Pearl
Super Smash Bros. Brawl
Legend of Zelda: Wind waker
Legend of Zelda: Ocarina of Time
Eternal Darkness
Super Mario bros. 3
Super Smash bros. melee
Paper Mario: the thousand year door
Super Mario Galaxy
Sim City

top 5 this gen

EBA
Brawl
MKwii
Galaxy
wild world ( might get dethroned by City folks )

top 10 are (its tough for me to do 20)
super mario world (snes)
donkey kong country (snes)
dont remember the name, but it was about zombie's (SNES)
final fantasy 8
final fantasy 7
gran turismo 1
mgs1
gran turismo 1
final fantasy 9
mgs4

i have to put the SNES games first, i played them when i was a little kid! I miss the old says! sniff sniff....

this gen:
COD4 (online only)
Mgs4
gears of war
halo 3
blue dragon

you can tell this gen sucks, no good rpg's and mostly shooters.

Top 20 of all time.

1 - Jak 3
2 - Jak and Daxter: The Precursor Legacy
3 - Ratchet and Clank
4 - Jak II: Renegade
5 - Crash Bandicoot
6 - Half Life 2
7 - Ratchet and Clank 3: Up Your Arsenal
8 - Counter Strike: Source
9 - Fable: The Lost Chapters
10 - Pokemon Yellow
11 - Crash Bandicoot Warped
12 - Tekken 3
13 - Rayman
14 - Call of Duty 4: Modern Warfare
15 - Uncharted: Drakes Fortune
16 - Resistance: Fall of Man
17 - Burnout: Paradise
18 - Super Mario Sunshine
19 - Pokemon Silver
20 - Team Fortress 2

Top 5 this gen:

1 - Call of Duty 4: Modern Warfare
2 - Uncharted: Drakes Fortune
3 - Resistance: Fall of Man
4 - Burnout: Paradise
5 - Team Fortress 2

Top five this gen-consoles only:

1) Bioshock (360)
2) Elder Scrolls IV (PS3)
3) Gears of War (360)
4) The Orange Box (360)
5) Halo 3 (360)

Top Twenty of all time-including PC games:
1) Bioshock (360)
2) Super Mario 64 (N64)
3) Command & Conquer (PC)
4) Halo: Combat Evolved (Xbox)
5) Warcraft II (PC)
6) Sonic 3 (Genesis)
7) Elder Scrolls IV (PS3)
8) Star Fox 64 (N64)
9) Sim City 3000
10) Street of Rage 2 (Genesis)
11) Grand Theft Auto: San Andreas (PS2)
12) Tom Clancy's Splinter Cell: Pandora Tomorrow (Xbox)
13) Mario Kart 64 (N64)
14) Super Smash Bros Melee (GC)
15) Resident Evil 2 (PS)
16) Goldeneye 007 (N64)
17) Tony Hawk's Pro Skater 3 (Xbox)
18) ESPN NFL 2k5 (Xbox)
19) Rise of Nations (PC)
20) Star Wars: Tie Fighter (PC)/ Star Wars: Rogue Squadron (N64)

Current;

Bioshock
Forza 2
Gears Of War
Call Of Duty 4
GTA4

Alltime;

Bioshock (360)
Duke Nukem: Total Meltdown (PS1)
Oddworld: Abes Oddysee (PS1)
Oddworld: Abe's Exoddus (PS1)
GTA4 (360)
Call Of Duty 4 (360)
Castlevania: SOTN (PS1)
Wolfenstein (PC)
Forza 2 (360)
Gears Of War (360)
Gran Tursimo 3 (PS2)
Tony Hawk Pro Skater 3 (PS1)
Tekken 3 (PS1)
Doom (PC)
Mortal Kombat Deception (PS2)
Super Mario 3 (SNES)
Batman Forever (GEN)
Half-Life (PS2)
Half-Life 2 (360)
Goldeneye (N64)

any great Horror games.

you should know, i know.

Im not typing >> Secret

Wow i don't even know if i can find 20 games i like, let alone rate them. here goes.

Okay they're not really in perfect order, but heres my top 20:

20. Goldeneye: Rogue Agent
19. Ratchet and Clank
18. No One Lives Forever (very under-rated)
17. Crazy Taxi
16. Halo
15. Elder Scrolls IV: Oblivion
14. Rainbow Six Vegas
13. Resistance Fall of Man
12. EA Sports NHL Series
11. Madden NFL Series
10. Star Wars Battlefront
9. Need For Speed: Hot Pursuit 2
8. Crash Bandicoot 2
7. Gran Turismo 4
6. Gran Turismo 2
5. James Bond: 007 Nightfire
4. SOCOM II: US Navy Seals
3. Crash Bandicoot 3: Warped
2. Call of Duty 4
1. Gran Turismo 3

Current Generation Games:

5. Uncharted: Drake's Fortune

4. Elder Scrolls IV: Oblivion

3. Resistance: Fall of Man

2. Rainbow Six: Vegas

1. Call of Duty 4: Modern Warfare

Haha i notice from your sig you own a wii and PS3 mabey buy a 360 there are a ton of good games =). I dont see how you couldnt name a few though....