Although most of us thinks ourselves as a good and clever player, I think it would be good to write down interesting tactics, good combos. Atleast myself enjoy to read these kind of posts.
That Spider Spawn+Web for example was interesting for me, because I haven't thought those summoned spiders are immune to Web. Of course I used usual: Greater Malison + Web, + Entangle + Stinking Cloud combo and ensured my kill with some Fireball, Cloudkill etc.
Another interesting thing was for me that Sunfire bypass through magic resistance. Is this right?

I usually put Greater Malison and Emotion in some sort of trigger or sequencer. It tends to keep my party from being affected.

I also have a hand in using Fireshield Blue together with Ice Storm or something similar with Fire damage Area effects.

It bypasses magic resistance.

See this thread: http://forums.blackwyrmlair.net/index.php?showtopic=2908

While it's mostly for new players those should find "interesting tactics" most useful.

Vampiric Touch damages golems.

...I've just read it the thread above, now my mages can damage something^^

--
Good old imba imba:
Chain Contingency: Helpless - self - 3x Projected Image
Cast Projected Image

viola 4 times your mage in action ... (doing this disables the summoning limit, allowing you to, well... summon 12 planetars or so^^)

--
Enemy mages seem to cast (combat) dispell spells only on mage/druid/cleric types... so a fighter immune to magic fire cold electricity death charm stun... will not be targeted by any spells of the enemy mage(apart from some summons).
((rumor)But it seems that their contingencys still work (sometimes?) on not protected members of your party outside their LoS.. but since they are not the target of dispells it shouldn't be a problem.(rumor))

Some Lichs & Dragons cast dispell magic only once, very early in the battle so if the dispelltarget runs very fast you can make him the only target.

--

Aerie with

Blade Barrier
Globe of Blades
Aura of Flaming Death (reduces enemys fire resistance!)
Fireshield Red
Fireshield Blue
and Prot from Magic weapons

is the ultimate hit me and I hurt you combination^^.

Well, this is the well-known cheesy method of creating an army of planetars, but as you already know, Project Image is replaced with a brand new spell in IA v4.3; so, this method will not work anymore.


No, none of the enemy casters fire their contingencies and triggers on targets who are out of their LoS.

Wrong. It bypasses magic resistance, that's all. It's effect doesn't "damage golems". If the golem is immune to the type of damage dealt: no damage.



Note that it won't work any longer in 4.3, as PI will be removed then.

Vampiric Touch doesn't affect the following types of golems:

From the game's standard golems: Bone Golems and Magic Golems are immune (it affects the rest)

From IA's new types of golems: Mithril Golem, Ultra Golems and Supreme Golems are immune (it affects the rest).

What about Sunfire? Does it bypass magis resistance?
Also it was new to me that Breach brings down the hardiness... It will make my time easier since I have never tried this on melee guys, and I have a hard fights when I was no able to kill melees who triggered his hardiness when he was hurted...

-.-

I always liked this spell page by Xyx. Several spell uses which I had never thought of, combinations, which spells counter which, etcetera.

http://members.chello.nl/~j.vanthull/BG2SR/Main.htm

Of course, Sikret has made some spell changes, but in theory you can get a lot of ideas from there.

Thanks Iroumen, I didn't know it and seems very useful.
I read very interesting things, just I am not sure if I understood sthing correctly. Usually when I want to cast with my F/I, I wait till his round starts, cast a spell, when spell casted press attack again, when new round starts, cast again. But I read in this site, that to attack and cast after you made all attacks is better. Is this right? If yes, how do I know when I delivered all attacks? Should I check in text messages among 100+ other messages?

This not some kind of bug for me btw that there are some spells which bypass magic res. Lower res ok, since this is the main purpose of spell, but Vampiric Touch, Sunfire etc. is a bug imho. I accept this is the rule in this game btw, so I used them yesterday.

Sunfire bypassing MR is an unfixable bug of the vanilla game.

Vampiric Touch doesn't bypass MR in the vanilla game; it's tweaked by Improved Anvil to bypass MR. See the readme.

This isn't so much a fighting tactic as general game advice: do NOT assume that pickpocket is useless because you can no longer steal from stores. In my game (I'm playing sorta a test-run until 4.3 comes out then will start a new game) I decided for the heck of it to pickpocket a few people with my blade and have already came up with at least one very good item and a variety of other stuff good for selling or using. I won't spoil with more details, but be sure to pickpocket some people!

Potions for pickpocketing are everything.

Early game I often try to drink some potions which enhance my pickpocketing abilities and just go around town picking everyones pockets. It gets me some gems or gold from nobles, some gold from commoners, and atkathlan guards or soldiers sometimes provide magic scrolls such as protection from magical weapons, true sight, minor spell turning or mislead (no idea why those particularly).
It gets you some nice cash for early items, as well as some nice early scrolls which may be useful in your adventures.

There are only a few important NPCs which you can pickpocket which normally have some nice items (riblad has a ring of regeneration or something alike in vanilla, but in Anvil it has been removed).