This line is covered briefly in the new Stonewall book (Sverre Johnsen, Ivar Bern). I won't give their analysis in detail, but they like 5...Nc6 (which was my first choice as well, before I saw the book), and give 5...c6 and 5...Nf6 as also playable. In the Asanov-Savon game they query 8...Kf8 and prefer 8...Bxd4.

I will post a couple of comments on the book in the appropriate thread, but I definitely recommend it.

The diagrammed position seems to be lacking a certain, je ne sais quoi.  Perhaps a Knight on g1?


A friend and I analysed a different variation:

1.d4 f5 2.Bg5 g6?! 3.e4! fe4 4.f3 Bg7 and white gets a very playable version of the Staunton as was played in the theoretically important game, Danielian-Rublevsky (1991). Black probably does better with 4...d5


The game continuation given here can also be played via a Staunton move order, but I don't see why white would play Nc3 first if 3.e4 really is good for White.

Regarding 5.Bc4, it may actually be a slower attack than the more traditional f3, and Eric has already pointed out a potential tactical reason why we rarely see the B go directly to c4.  It may be stronger on d3 anyway.

After 1.d4 f5 2.Bg5 g6 3.Nc3 Bg7 4.e4 dxe4 5.Bc4 Nh6, I too like Black but I think after 6.Nge2 (or maybe 6.h4 or 6.f3) 6...c6, that White should try 7.d5!? and retain some compensation.

After writing the above I messed around with this gambit on Rybka.  The gambit seems more dangerous than I initially thought.  First of all 5...Nf6 might actually be best and there's also 5...Nc6 which could be tried but I'm not too sure about it.  After 5...Nh6 6.f3!? exf3 (probably 6...e3 is best) 7.Nxf3 c6 8.0-0 d5 9.Re1 is very dangerous despite the fact White is down a lot of material.

Yesterday, in a rapid game my oppponent plaid this with white:
1.d4-f5 2.Bg5-g6 3.Nc3-Bg7 4.e4-fe4 5.Bc4!?
http://chessup.net/php/pictureParser.phpfen=rnbqk1nr/ppppp1bp/6p1/6B1/2BPp3/2N5/...;
It seems this move is nearly never plaid: I just found one game (Asanov-Savon, St-Petersburg, 1994 http://www.chessgames.com/perl/chessgame?gid=1331976) where black continued with Nf6 and lost in 21 moves.
I plaid c6 but after Bxg8, my position was quite difficult and I eventually lost after blundering a bishop some moves later.
What do you think of this move and what would you recommend to black?