This thread can be used to collect all of our findings related to the picture regarding PAYDAY's second birthday, below is what I've found so far.

One of the most obvious things is an area on the map (right between Dallas & Wolf) that's circled and has arrows pointing at it. Looking this building up on Google Maps, it appears the embassies to Liechtenstein, Iceland and (drumroll) Sweden are here.

Other buildings are also marked, just above Wolf's head, the Georgetown University is marked, to the left/top left of Dallas' head, 1312 29th St NW & 2811 P St NW (addressess are approximations, the street they're in is accurate though) have been marked with an X, though a quick Google search reveals nothing special about either of them.

I'm trying to find the addresses to the other three crosses on the right hand side of the map, but I found something odd in the meantime:
to the left of the exclamation mark on the map, there appears to be a body of water, that isn't there in real life, nor is there anything of that shape (and nope, it's not McMillan Reservoir, they don't match, and the longtitude (lengthitude? it's north-ness) is off). If you want to look, the bottom point of the mark-thing is at the Thomas Circle Park.

The dot of the exclamation mark appears to be centered around (the vicinity of) Burke Park, though the only thing near there I could find is an elementary school, and I very, VERY highly doubt we're going to be doing anything with that...

I'll post more when I've found the last three marks...