Here is mine:
PG - John Stockton
The best pure passer / playmaker ever to play the game, and the perfect guy for any star studded line-up because he's perfectly only taking 4 shots a game if that's what is best for the team - yet if you need him to score more on any given night he's more than capable. As a bonus he's one of the most efficient offensive guards ever to play the game (career 51.5% FG, 38.4% 3PT, 82.6% FT, 1.44 PTS/FGA, 3.75 AST/TO) as well as being one of the best defensive Point Guards of all time. Plus he's a proven winner, making the playoffs every single season of his career (something like 18 straight seasons) even at the age of 40. His ability to stretch the floor with elite shooting makes him a perfect fit in any era, with any teammates.
SG: Michael Jordan
Sorry, I know it's unoriginal but I had to go with MJ at the two. He's the greatest SG to ever play the game, one of the most dominant defensive guards in the history of the game, an absolute winner and competitor of the highest level, o0ne of the most clutch players in history, and one of the most dominant one-on-one scorers ever to play the game.
SF - Larry Bird
For all his strengths, MJ wasn't ever really a great outside shooter - so to ensure the team can still excel in today's game, I figured you'll want at least 3 deadly shooters on the court with him. I also think that you always want guys who are versatile - guys who can play/guard multiple positions and contribute in many ways. Larry Bird is one of the best shooters to play the game, but he was also passed the ball like a PG and rebounded like a centre - and was aan outstanding defender. Having Bird and Stockton on the perimeter gives MJ all the space he needs to get in to the paint at will.
PF - Kevin Garnett
This may seem an odd choice, as I'm sure there are better PF's who have played the game. But I select prime KG for this team for a number of reasons. Firstly, he's well and truly one of the greatest passing big men ever to play the game (almost 4 APG for his career) and that makes him deadly on a team that also features Stockton, Jordan, Bird and Shaq (who himself, was a skilled passer. That's a lot of ball movement right there. Secondly, KG had a similar mentality to Stockton in that he was a very unselfish superstar - a very capable scorer, but actually PREFERRED to get teammates involved whenever it was possible. This unselfishness makes him a fantastic fit on a team where Bird, MJ and Shaq will already be battling for touches. Then on top of that, you have KG's elite agility and explosive athleticism - a stark contrast to Shaq's sheer size and power. With those two guys side by side you might have the scariest defence in the history of the game. Then on top of that you also have KG's elite ability to hit those long two's (and could no doubt step out and hit the odd three if he had to) which helps to stretch the floor and give MJ and Shaq room to work. Finally, there is the mental aspect. Between Stockton, Jordan, Bird, KG and Shaq - you have got 5 of the most mentally intimidating players of all time. All of those guys have the elite ability to get in to an opponents head with their combination of limitless trash talk and physical play.
C - Shaquille Oneal
I considered a variety of other players (such as Kareem and Hakeem) but at the end of the day I settled on Shaq, simply because I feel every team benefits from a dominant paint presence, and Shaq may well be the most dominant paint player in NBA history. Between his unstoppable inside scoring, his elite rebounding and shot-blocking (career 11 RPG, 2.3 BPG), Shaq was a guy who utterly dominated the paint when he was fit and healthy. There were elite big men who were literally scared to play against him because he was THAT monstrous a force. Nobody wants to drive in to the paint when they have a 315 pound (at his most athletic) monster waiting to knock them to their butts - and he was not afraid to do exactly that.
6th man - Lamar Odom
In his prime Odom was a 6'10" guy who could genuinely play and defend all five positions on the court. He could score, shoot, pass, rebound and handle the ball as well as being an excellent and incredibly versatile defensive player - and he was a legit 6th many for a number of his prime seasons for the Lakers. He was the X-Factor for a LA in a couple of their finals runs and created massive matchup problems for opponents off the bench. Hard to think of a better 6th man who can come in at literally any position and contribute to your tem in just about any way you could possibly imagine, and doesn't need the ball to contribute.
That's my all time team. I think it would be frighting as ell for any team to play against!