I like simply 1.e4 e5 2.Nf3 d6 3.d4. It leads to concrete play quickly so no running around in circles is required. You can castle long against the 3...exd4 Philidor. Something like 4.Nxd4 Nf6 5.Nc3 Be7 6.Bf4(!) O-O 7.Qd2 is normal. If they try the Hanham (1.e4 d6 2.d4 Nf6 2.Nc3 e5 3.Nf3 Nbd7) I don't think you can get complications until the middlegame. I don't know the theory anyway so I just try to develop normally.
What's great about the Philidor is that there aren't any opening tricks for either side except in special cases. So even though Black is cramped both sides have to play concrete moves for anything to happen.
I also play the "boring" giuoco pianissimo and I still get tactical opportunities. I think the main thing is to get open positions.
In Live Chess Standard, I am under 1200, sometimes peeking to 1250. It's not a high rating, and blunders happen frequently. If you are rated over 1200, think back on your under 1200 days, and tell me which openings for White, and defenses for Black, caused the most blunders.
Why? I do Tactics Trainer daily, with a TT rating over 1200, and want to play openings and defenses that yield the most tactical opportunities. I figure that by playing these lines, learning the best theoretical moves along the way, while continuing with tactics trainer, I will experience greater success in Live Chess, maybe hitting 1300 sooner.
What about the King's Gambit? Most of my opponents play 1...e5 to my 1.e4. So, I would be able to play more KG than any other opening, since the second move by White starts the gambit, with 2.f4.
I like the attacking ideas found in the Evan's Gambit, but my opponent's would need to cooperate for three moves before I can play 4.b4. Last night, after three games with the White pieces, I never got a chance to play 4.b4. I often see this: 1.e4 e5 2.Nf3 Nc6 3.Bc4, but more often than not, I get something other than 3...Bc5. I suppose I could play 4.Ng5 after 4...Nf6, which creates complications.
What I see more than anything else is The Philidor Defense. Are there ways to complicate things against this defense? Playing White, how can I take advantage of Black's hole at d5? Should I play 3.d4, or 3.Bc4 first?
Well, I probably rambled just a bit, but I'm very interested to hear about openings and defenses, appropriate that present the most complications, with plenty of opportunities for mistakes and blunders. Thanks!