While I generally like a deeper game, I have to agree with others. When starting out I leaned towards the more is better approach and that worked well as I grew the collection. So I would lean towards two good games.

Personally I'm not a fan of T2. A little repetitive. I prefer GetAway. Not a super deep game, but a real crowd pleaser. Your kids and guests will love the super charger. Very cool effect. Not sure on price, but Shadow is a fantastic game as well. Not sure how much more it is compared to T2 or GetAway.

I think I would go with 3 games assuming you have the room. Instead of FG + DMD maybe go DMD, Sys 11 and another game? Lots of great Sys. 11 games. Maybe you find a deal and get can 2 DMDs plus Sys. 11 for similar money as FG + DMD.

Good luck!