I'll just tell you all my current lineup right now so you can make a better judgment.
C - Matt Duchene C - Logan Couture C - Brad Marchand C - Tyler Seguin RW - Corey Perry RW - Jarome Iginla RW/LW - Rick Nash RW/LW - Ryane Clowe LW - Jamie Benn D - Zdeno Chara D - Mark Streit D - Ryan Whitney D - James Wisniewski D - Travis Hamonic G - Henrik Lundqvist G - Jimmy Howard
Seriously, I think this is a bad trade for you. Lets start with saying that while Giroux and Tavares are killing it right now, you shouldn't panic and make a rash trade like this. You likely picked Nash ahead of Giroux and Lundqvist ahead of niemi at the draft for a reason. It's a long season and Duchene is poised for a good one. Also with howard as a backup you really can't afford to lose The king right now.