Caps' Needs

So, it's NHL trade deadline time. There are tons of rumors flying around involving multiple teams and players, some of which will probably prove to be true.

I've heard Niklas Backstrom (the Minnesota goalie, not the Caps center) and Chris Pronger are on the Caps' list, while Michael Nylander, Karl Alzner and other Caps are on other teams' radars.

I watch a team like Philadelphia beat up the Caps almost every time we play them. I also watch a low-level West-coast team like LA come in and beat the Caps to every loose puck. It seems that, outside Ovechkin and Bradley, the Caps are missing a strong physical aspect to their game. But it also seems, based on the lazy penalties and losing races to pucks, that the Caps also lack speed depth (again, line 1 is OK).

So I'll ask this: What do the Caps need, who do the Caps need, who should go, and who is untouchable?