In my quest to build a level 20 mainly-fighter character in D&D 3.5, I have stumbled into enlightenment. You don't need to counter the magic. You don't need to prevent the magic. You need to ignore the magic; make it irrelevant. Massive amounts of fire damage got you down? Get yourself some fire immunity. Instant death effects threatening? Become immune to them. It does not matter if your opponent pins you down and has every opportunity to whale on you. If you survive everything they have, you can start to counter them. If you're not dead, they don't win. You can beat them eventually, or they will give up. Failure is impossible, and thus victory is assured.
Mainly I'm happy that my level 10 Fighter/1 Pious Templar/2 Level Adjustment/2 Warblade/5 Warforged Juggernaut was able to defeat an epic leveled force dragon with 36 sorcerer levels. The look on my DM's face was priceless.
Him: Thanor makes his spellcraft check to cast Pin to the Sky. You are pinned to the sky, and cannot move.
Me: Alright.
Him: Thanor makes a spellcraft check to cast Hellball.
Him: He succeeds. You are pinned, and thus cannot make the reflex save. Take 10d6 Fire damage, 10d6 Shock damage, 10d6 Ice damage, 10d6 Sonic damage, and 10d6 Acid damage.
Me: Okay, zero damage. I'm immune to all of those.
Him: ಠ_ಠ
Me: (~_^)
Him: Thanor makes a spellcraft check to cast Vengeful Gaze of God. Wow, that's a DC 419 check he just made. Maybe this dragon was too powerful. *snicker* Roll reflex to avoid full damage.
Me: I fail my reflex save.
Him: Okay, 305d6 damage. Thanor takes 200d6 damage as recoil, but scrapes on through alive.
Me: Okay. *roll concentration* I use Mind Over Body to replace my fortitude saving throw from Wedded To History with a concentration check. I now have one hit point remaining, though I lose 2 constitution. Err... wait, I'm immune to energy drain. I'm just alive, then.
Me: I charge Thanor and full attack with pounce. *roll dice* Natural 20, automatically hits. *roll dice* 129 damage.
Him: ....
Me: What?
Him: You have defeated Thanor the Godslayer.
Me: (°_°)
Him: (╯°□°)╯︵ ┻━┻
It's always a good time when the players can defeat the DM's "epic dragons fall, everyone dies" plans. On the other side of the table, my compadre used a thousand-limbed soulknife to launch literally 1,000,000 attacks at the various swarms of lesser dragons while I fought the big world-crushing one. Ultra high powered campaigns are my favorite.