My number #1 favourite rule from the DMG is very close to the front of the book. It's the one about throwing all the rules away for the enjoyment of the game.
Personally, Metus and Sam500, I don't think you're really on a different wavelength. Metus uses the rules to make everything fiar and balanced. The rules will let you get away with an awful lot if you read them right. Sam500 does things more spontaneously but keeps things fair. Two different roads toward the same goat. Is either better? No, everyone's having fun, so the goal's been achieved at both tables.
Consider yes, the emphasis should be on the 'consider'. I am a consider yes DM, if my players want to do something, I generally let them do it. I did not let my newbie wizard use his snake familiar as a whip, however. That was just stupidity. My more experienced wizard player wants a Staff of the Magi. Fair enough, they're 23rd level now, but he's gonna have to pry it from the Dracolich-riding Lich-Queen Demigoddess Vlaakith's unlifeless fingers. But I do try to encourage creative uses of spells, items and abilities, so I err on the side of yes. If one of them expresses the need for something not too outlandish, I generally say yes as well.
Now it's pet peeve time. Game balance is a myth. DnD is decidedly unbalanced and no matter how hard you try to follow the rule of law won't change the fact that the system is deliberately unbalanced. Magic Missile and Fireball are popular because they are simply better than all the other spells at that level. Scorch is the new 2nd level unbalancing act. The ammount of assets, powers and abilities a canny, powergaming, party can accumulate using the rules is amazing.
Balance has little to do with the rules and alot for what you do at the table. Following the rules explicitly and turning a blind eye to those who abuse said rules only feels stable and safe. Never looking out of the box and never fudging a die roll for or against the players for the sake of fun may deprive you of enjoyment that may have been had otherwise.
I often fudge results. If the game's bogging down, I throw in a wandering monster to kick it up a notch. I often tailor Wand of Wonder results to suit an encounter rather than rolling on the limited d100 table. These decisions are by no means arbatrary, I have a modus operandi, a goal and a method to my madness.
Let your players powergame and allow them to work the rules like cheap prostitutes, there's always a bigger fish and you can powergame just as easily as they can. I took one look at The Cathezar from Bastion of Broken Souls and knew she'd be mince meat in 2 rounds, if she was very lucky and got the drop on the PCs. So I ramped her up a bit. My 23CR Multiheaded, 12-limbed, Marilith/Kyton (optimized for spiked chain attacks with the Perfect Multiweapon Fighting feat) struck fear into the hearts of my 15th level players throughout the entire adventure, they literally ran from her into the tender arms of a 26CR dragon half-fiend (they were 18th level by then) who they found to be much easier prey.
Which goes to show you how whacked the CR rules are.