Interesting tactics, good combos Options

[Shadan]

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?

[Shadan]

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.