I would recommend sticking with d5. As dozeoff rightly says 2...c5 leads to a completely different (and difficult to play) defence. 2...d5 might result in something boring but the same is true for d4, you can't prevent your opponent from playing an exchange structure.
And after all i think that calling the exchange boring at our level is an overstatement. Sure, if you have a 2200+ elo rating then maybe the symmetrical pawn structure makes this variation boring against an opponent of similar strenght. But for patzers like me and you the game is most likely going to be decided by a blunder later in the game; so just try to avoid total symmetry by developing your pieces in different places than your opponent's. You will find that the game can be as fighting and sharp as the wildest variation of the sicilian. Sometimes being not a master is a good thing ;)
I say stay with 2. ...d5. After 1. e4 e6, 2.d4 d5 White can play 3. exd5 anyway. This i the exchange variation and is considered to be White's "boring" choice. See if you can find some commented games by masters online and learn a little from them.
2. ...c5 is as good but turns the game into a Sicilian opening (1. e4 c5, 2. Nf3 e6).