Well...........Leisure Suit Larry Collection is the Vivendi re-release of the series. It includes LSL 1 - 6 I believe.
Leisure Suit Larry Box Office Bust is the newest release and is actually Larry's nephew I think. It is a follow up on Leisure Suit Larry: Magna Cum Laude which, in my opinion, was a travesty to the series name. Neither LSL Box Office Bust or LSL Magna Cum Laude included any input from the creator, Al Lowe, and since I am a big fan of said creator is off putting to put it mildly.
You can find an interview
here and a review
here. I won't be buying the game unless I hear from other gamers that they actually did go back to the original intent of the games and then might boycott the game just because they snubbed Al Lowe but that's just my opinion.