Just to say that konnichiwa is owning everyone with 30 games !

Let me see :

Rayman 2 ( Psone ) finished it and collected basicly everithing :P

Quake 2 : finished it 2 times ( the PC version of course )

Silent Hill 2 ( PC/PS2 ) tried it to finish both versions , but I never got into the mood :?

Alone in the Dark ... well back than this game was the shit ... I played it a lot , but eventually didnt finished it :? ( MSdos )

Maniac Mansion : DOTT : played it a lot ... one of the best adventure game of all , but one of the hardest to ... played it on my ,, new " 486 ... lol , the good times :)

Space Invaders : played it hell lot , and got some awesome scores for it :)

Prince of Persia : Sands of time : man I finished this soooo many times , I really dont know actually how many times :? Im playing it again right now . Best game of all IMO , hands down :)

I played many more from that list ( MGs2 , FFVII , Megaman 2 etc. ) , but this are the ones that Ive got into a bit more ... or really really deep :)

Updated list...

99) Rayman 2 (Beat)
97) Silent Hill 2 (Beat)
96) Wave Race 64 (Played multiplayer a lot on my N64 back in the day)
94) NiGHTS (In the process of trying to beat it)
90) Okami (Just a bit; waiting for the Wii version)
86) Perfect Dark (Multi, mostly)
83) World of Warcraft (Sadly... and why the &%$# is this on the list in the first place??)
81) Space Invaders (On an Atari 2600 :) )
77) Star Fox (Beat)
76) Final Fantasy VII (Beat, but only because I forced myself to so that I could say that it sucks. =P )
75) Goldeneye (Beat)
73) Resident Evil (Beat on the Gamecube)
72) Mechwarrior 2 (Beat)
71) Planescape: Torment (Beat about a half-dozen times)
69) Metal Gear Solid 2 (Beat)
67) Mega Man 2 (Beat)
64) Total Annihilation (Messed around endlessly with skirmish mode back in the day)
62) Wolfenstein 3D (Played, but never actually beat)
61) Phantasy Star IV (Played enough to know that I really didn't like it)

That list sucks, FFVII only at 76, what a joke.

Updated List for me (played, not necessarily owned):

99 Rayman 2: The Great Escape
98 Quake 2
87 Advance Wars
82 Syndicate
81 Space Invaders
79 Secret of Mana
78 The Legend of Zelda: Link's Awakening
77 Starfox
76 Final Fantasy VII
67 Megaman 2
64 Total Annihilation
62 Wolfenstein 3D

60 Prince of Persia

59 Command & Conquer: Red Alert

55 Final Fantasy II (II in U.S, IV in actual numerical order)

54 Contra (First video game I ever played)

52 Dune II: The Building of a Dynasty

51 Sonic the Hedgehog

18 games so far 

My updated list:
98. Quake 2
97. Silent Hill 2
95. Bionic Commando
93. Wipeout 3
91. Pilotwings
86. Perfect Dark
84. Day of the Tentacle
83. World of Warcraft(doesn't deserve to be there)
81. Space Invaders
79. Secret of Mana
78. Legend of Zelda: Link's Awakening
77. Star Fox
76. Final Fantasy 7
75. Goldeneye
73. Resident Evil
69. Metal Gear Solid 2
67. Mega Man 2
63. Virtua Fighter 4
62. Wolfenstein
60. Prince of Persia
59. Command and Conquer: Red Alert
58. Mike Tysons Punch Out
54. Contra
51. Sonic the Hedgehog

24 games so far

99 Rayman 2 (I think I own this game three times beated it on PS one and PS2 and I loved that the games were not whole the same on the system).
98 QUAKE 2 (Oh man that was a sweet game I only own it on PC though).
97 Silent Hill 2 (Sometimes I wished I didn't all those sleepless nights X_X).
96 Wave Race 64 (Yup but I don't know if I got all the unlokacbles).
95 Bionic commando ( I would not put this game in my top 100 though).
94 Nights (And now it will come to PS2, This deserves another buy from me).
93 Ultima II (I got this on a collectors disc don't know it is legal).
92 Wipeout III (Like Wave Racer 64 I don't know if I got all the unlockables)
91 Pilotwings (I don't own it anymore so sad).
90 Okami (Beated it two times my second time under 10 hours, will buy it for Wii for sure).
89 Alone in the dark (Like Wave Racer 64 don't know if I finished it, I guess so).
88 Star Wars arcade (My uncle owns one of this he also bring this thing on conventions).
86 Perfect Dark (YEES AWESOME GAME).
85 Mafia (I love those Maffia/Yakuza games).
82 Syndicate (NOrmally I own this on PC and I think on Genesis not sure though).
(81) Space invaders (I don't know could you beat it?).
80 Ninja Gaide Black (Will also buy the remake on PS3).
79 Secret of mana (And I just found out that I don't own the prequel sad).
78 The Legend of Zelda (Who didn't beat this game?).
77 Star Fox (Must have).
76 FFVII (Yes).
75 Golden Eye ( PDZ and GE are probably the only FP shooters I enjoyed on a nintendo).
73 Resident Evil (Beated whole the main serie).
69 MGS2 (It is still my favourite MGS I loved the details especially on the schip).
68 POP (Yup all three games of them in that generation).
67 MM2 (When Mega man's were still fun).
66 Burnout 3 (All of them).
63 VF4 Evo (You could not really beat it though).
62 Wolfenstein 3D (Who didn't?).
61 Phantasy star IV ( I am not sure anymore but I thought it was my first PS game).
60 POP (POP yup it is the reason that I bought the other games later on PS2)
57 ICO ( Yes I beated but I never started with a 2nd playtrough I heard that the girl her words are subbed then).
55 FFII (Yup, very strange that this game scores better than FFVII). 
54 Contra ( I had this on the gameboy, oh man one of the reasons why I loved my GB).
51 Sonic (Sad that their are no good games of Sonic anymore).

I don't know how many I have beaten, but I have played 28 of those games extensively.

... and MGS2 in the top five? Are you guys joking? I rated it a 7.0. I hated that game and only gave it a decent score because of its technical achievements for the time.

update:

97- silent hill 2
90 - okami
86 - perfect dark
83- world of warcraft
81 - space invaders
80 - ninja gaiden
77- star fox
76- final fantasy VII
75 - goldeneye
73 - resident evil
69 - Metal Gear solid 2
68 - prince of persia: sands of time
67 - mega man 2
66 - burnout 3: takedown
56 - NHL 94
55 - Final Fantasy II(IV)
54 - Contra
51 - Sonic the hedgehog

These are the ones I've played extensively, Total Annihilation and Quake II a played almost exclusively in Vs. mode.

Quake II
Silent Hill 2
Wave Racer 64
Advance Wars
Day of the Tentacle
Space Invaders
Secret of Mana
Legend of Zelda Link's Awakening
Star Fox
FF7
Golden Eye
Sam and Max Hit the Road
Mech Warrior 2
MGS 2
Mega Man 2
Total Annihilation
Wolfenstien 3D
Red Alert
FF2
Sonic the Hedgehog