I just was about to go to bed but I want to answer to this thread first.
I have played 2.c3 for some time now, and I have had very good success with it. The fun starts when I play 2. c3 and see the annoyed look on Villain's face.
The move 2... Qa5 that Heron proposes is mostly crap in my opinion. Sure, White can't play 3. d4 but it places the queen rather early on a square of doubtful value. I surely am not annoyed when I see 2..Qa5, but delighted. It's like a psychological victory that Black avoids the main lines. It reminds me of a fun game I played this year against a better opponent:
1.e4 c5 2.c3 Da5 3.Sf3 Sc6 4****4 e6 5.0-0 b5 6.Lb3 c4 7****2 Sf6 8.d4 cxd3 9.Dxd3 e5 10.Lg5 Le7 11.Td1 0-0 12.Sbd2 Td8 13.Sf1 Lb7 14.Se3 Sh5 15.Lxe7 Sxe7 16.Dd6 Sg6 17.Sxe5 Sxe5 18.Dxe5 Sf6 19.Sc4 Da6 20.Sd6 Db6 21.Lb3 Tf8 22.h3 Lc6 23.De7 Sxe4 24.Lxf7+ Kh8 25.Sxe4 1-0
Okay, Black could have played better, and my 4. Bc4 is not best either (4.d4!), but I just love the position after my 20th move.
Speaking from White's point of view, the line I want to see the least is 2..Nf6 and then the main line 3. e5 Nd5 4. d4 cxd4 5. cxd4 d6 6. Nf3 Nc6 or 6...e6. That doesn't necessarily mean it is best but it is the hardest Black setup to play against (for me personally, I don't know about what's considered best theoretically). And yes I know about the 5. Nf3 / 7. Bb3 option.
I love playing against 2...d5 because the resulting positions suit me. In principle however, it should be fine for black as most often the game ends up in an IQP position where White's pieces aren't placed optimally.
I am also not really convinced about 2..e6 as this gives me the option to transpose to an advance French which I am fine with playing; and of course playing the exd5 lines is also totally fine for White.
To summarize, I usually am very happy with the positions I get with 2. c3. Surely, theoretically 2. Nf3 is probably better, but I don't play against grandmasters, so the most important thing for me is getting into positions I like and know what to do in. And with regards to this aim 2. c3 is the nuts.