A: You're playing it wrong if you're not enjoying yourself. Life's too short to waste being frustrated at D&D. Since everyone feels this way, something that might help is if your DM follows the actual rules for designing encounters that your party can handle as layed out in the DMG.
B: Sounds like everyone's having fun, you're doing it right and by the book. There's a reason we pay other people to design our games for us, and this is an example of why.
C: If no one's liking it, you're not doing it right.

Try breaking some of the rules, or just willfully ignoring them. It might be good to try an abstract combat system, like X, so that you get less bogged down in tactics.
D: Sweet. Continue to rock on. Not really my style, but as long as you make the game fun for you guys, what does my style matter? It doesn't.
E: You're a little off. You might want to talk to your DM about slowing it down a little bit, maybe offering you more treasure instead of another level here and there, letting you get used to your powers before you rocket off the charts.
F: Good show, glad you feel like you really earn everything you put into it.
G: Since nobody liked that, you may want to try ignoring the rolls and just talking it out, or having the DM assign circumstance bonuses based on how well you act out the scene. Or, if it's important for you to succeed, talk to the DM about how challenging his opponents were, maybe he was using something a bit too tough for an easy victory.
H: Everyone thinks this way, so have the DM look at the table for Wealth Per Level again. Then he can hold off until you need more treasure, giving you a chance to get used to your amazing gear for now! And don't be surprised if the combats are a bit tougher because of it.
I: Congrats! Glad you like the game. Next maybe you can kill Zeus!

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IMHO, role-playing right is role-playing to have fun, even if you don't adhere to the rules. The D&D rules are there to try and help you have fun, and most of the time, they work really well like that. Sometimes, they don't, and that's why we have Rule Zero. Which basically means that D&D is whatever the heck you decide you're going to make it, d12s for attack and all. You could take GURPS Technomancer out of the package, call it D&D, and be correct because of Rule Zero.
Of course, I'd probably ask you why you don't just say you're playing GURPS. I can never tell you you're not playing D&D, though.