The best openings are the main line ones, which are typically somewhat complex. For example, the Ruy Lopez. You are going to need tactics whether you play e4 or d4 --- e4 will help you become tactically alert faster.
I like the e4 repertoire in the Opening According to Anand by Khalifmann (Chess Stars Publishing). The opening style is active positional (like Anand), but not excessively risky. If you can't get these books, play through a lot of e4 Anand games instead.
e4 and d4 are both really good openings for different reasons. I switch back and forth depending on what mood I'm in, but I often stick with d4.
I say, pick an opening that your style of play goes with. It doesn't matter how "good" the opening is if you can't back it up with play and a solid middle game. Personally I prefer closed games. The claustrophobic, congolomerate of pieces that that often ends in a "domino effect" of piece captures suits my thinking.
The fundamental difference between e4 and d4 is one of perspective and style. I find e4 to result in sharper, more varied play. ... c5 (Sicilian), ...e5 (Ruy Lopez, usually), ...e6 (French), and ...c6 (Caro-Kann) result in 4 sharply different games. Also, following ...e5, you can see the Philidor (...d6) or Petroff (...nf6) relatively frequently. In all cases, you need to know how to properly abuse White's advantage and attacking chances.
Fischer played e4 religiously, which is enough for me, but also, I believe that though the early and middle-games vary sharply in terms of tactics for White, the typical positional requirements are relatively consistent throughout all the openings. Bishop pairs are more likely to be abused, opposite side castling is very easy to achieve out of many lines, resulting in similar, sharp chances for White, and I find the initiative as White is easier to use, although that's based on playing against 1.d4 as black and not actually playing the opening myself.
One thing I've found is that when low-mid level players stick to openings that suit their "style", they never learn anything and improve as players.
I was stuck at 1400 USCF rating for over a year, because I played passive, defensive openings, thinking it was "safer" and "suited my style". I lost a lot of games where nothing happened and it lasted a lot of moves, but my opponent somehow ended up with a better endgame and played it out better than me. I wasn't sure what I did wrong, so I never learned anything from those losses. Playing defensively only suited my style because I really needed to learn how to attack.
In the last 6 months, I've spent a lot of time playing wild, attacking gambits. My rating dropped about 100 points at first because I wasn't used to that style of play, but I just rebounded to a new high. I've lost a lot of games along the way, but the mistakes are bigger, more obvious, and easier to learn from, so I learn a lot more from these games than I ever did when I was playing quiet openings.
This is why I recommend classical attacking openings for beginners.
--Fromper
I am having trouble finding a comfortable opening. I am using e4 right now, but I was wondering if one is better than the other? Does your style of play, affect what opening you should adopt? And are some more more difficult than others?