Games that try to do both SP and MP usually fail lol.
Well I'm saying that with the exception of probably COD series.
But COD only attracts such a large multiplayer crowd because no matter how bad you are at the game, u can still enjoy it.
Definitely put multiplayer. Single player games are one off things. I finished COD6 in like 3 days (not playing it allday obviously, just from when i installed), and got bored and have not touched it since.
I've been playing CSS competitively since 2008 and still do, because the multiplayer is great
Not saying it's the best game, just what I think.
If you look at Steam Statistics, the top played games are all multiplayer.
1. COD6 - Multiplayer
2. CSS
3. CS1.6
4. TF2
etc
Probably in the first few days of release the SP games would have a bit of playtime.