Getting 100% is one thing, getting 1000/1000 achievements will be another.
I was curious to know what kind of Achievements there'll be for the Xbox version, so I Googled it and found the following list:
http://www.360-hq.com/Grand_Theft_Auto_IV_Xbox_360_Achievements-256.htm
There are 50 achievements with a total of 1000 points available
Off the Boat - Complete the first mission.
One Hundred and Eighty - In a darts game score 180 with 3 darts.
Pool Shark - Beat a friend at pool.
King of QUB3D - Beat the High Score in QUB3D
Finish Him - Complete 10 melee counters in 4 minutes
Genetically Superior - Come first in 20 singleplayer street races.
Wheelie Rider - Do a wheelie lasting at least 500 feet on a motorbike.
Gobble Gobble - Score 3 strikes in a row, a turkey, in 10-pin bowling.
Driving Mr. Bellic - Unlock the special ability of taxi.
Rolled Over - Do 5 car rolls in a row from one crash.
Walk Free - Lose a 4 star wanted rating by outrunning the cops.
Courier Service - Complete all 10 package delivery jobs.
Retail Therapy - Unlock the special ability of buying guns from a friend.
Chain Reaction - You must blow up 10 vehicles in 10 seconds.
One Man Army - Survive 5 minutes on 6 star wanted level.
Lowest Point - Complete mission 'Roman's Sorrow'
Over Fulfilled - Complete all 10 Exotic Export orders.
Manhunt - Complete the most wanted side missions from the police computer.
Cleaned the Mean Streets - Capture 20 criminals through the police computer.
Fed The Fish - Complete the mission 'Uncle Vlad'
It'll Cost Ya - Complete a taxi ride without skipping from one island to another.
Sightseer - Fly on all helicopter tours of Liberty City.
Warm Coffee - Successfully date a girl to be invited into her house.
That's How We Roll! - Unlock the special ability of helicopter.
Half Million - Reach a balance of $500,000.
Impossible Trinity - Complete mission 'Museum Piece'
Full Exploration - Unlock all the islands.
You Got The Message - Deliver all 30 cars ordered through text message.
Dare Devil - Complete 100% of the unique stunt jumps.
Assassin's Greed - Complete all 9 assassin missions.
Endangered Species - Collect every hidden package in the game.
Under the Radar - Fly underneath the main bridges in the game that cross water with a helicopter.
Dial B For Bomb - Unlock the special ability of phoning for a bomb to be placed.
Gracefully Taken - Complete mission 'I'll Take Her'
Liberty City (5) - After meeting all possible friends, the ones left alive all like you above 90%.
No More Strangers - Meet all random characters.
That Special Someone - Complete mission 'That Special Someone'
You Won! - Complete the final mission.
Liberty City Minute - Complete the story missions in less than 30 hours.
Key To The City - Achieve 100% in 'Game progress'
Teamplayer - Kill 5 players who are not in your team, in any ranked multiplayer team game.
Cut Your Teeth - Earn a personal rank promotion in multiplayer
Join The Midnight Club - Win a ranked multiplayer race without damaging your vehicle too much and with damaged enabled.
Fly The Co-op - Beat our time in ranked versions of 'Deal Breaker'
Take It For The Team - Be on the winning team in all ranked multiplayer team games.
Top Of The Food Chain - Kill 20 players with a pistol in a ranked multiplayer deathmatch.
Top The Midnight Club - Come first in 20 different ranked standard multiplayer races.
Wanted - Achieve the highest personal rank in multiplayer.
Auf Wiedersehen Petrovic - Win all ranked multiplayer variations, all races and 'Cops 'n Crooks' as both sides.
Let Sleeping Rockstars Lie - Kill a Rockstar developer in a ranked multiplayer match.
was sold-out within the first day... I could only imagine what GTA4 would be like. So I'm happy to confirm that my copy is now secured... and for $100AUD... which is quite good, considering it's $120 everywhere else. 
. Online chat sounds great... and the mini games... well, everything sounds great! 👍 👍 
) will be hitting this 10+ hours a day. Yes I'm jealous.
