I don't know if Projected Noise has gained any degree of usefulness lately, but I'd suggest waiting a bit before committing to it. Maybe Doc Feelgood could share some slightly more experienced light on the matter.
As for gods, I'd really suggest Nemelex Xobeh. Nemelex is usually awesome, and Spriggans have the best aptitude for evocations, which is what card usage is based off of. Their invocations (used for Zin's powers, as well as most other gods) leave a little something to be desired.
Trog could also grant some interesting benefits. A berserking Spriggan is something to be rightly feared... But most of his abilities put a pretty heavy cost on your stomach.
Yredelemnul can give you a use for all those corpses that you won't be eating, although the zombies wouldn't have a chance in hell of keeping up with you (but you can use the "recall" ability to have them suddenly show up to protect you or gang up on a victim). The minion gifts are generally pretty nice, and life draining is always good fun.
EDIT: Oh, one thing I forgot about... You can occasionally confuse enemies with Zin's preaching. Attacking a confused enemy can deal extra damage via the stabbing skill, which assassins usually have in spades. You can also bore them to sleep.
EDIT2: Alright, I gots a question for ya 'sperienced types... I'm currently running a deep dwarf geomancer whose goal is to eventually start worshiping Yredelemnul. I've been relatively lucky so far, and I ended up getting a pretty decent dagger of venom early on that I could supplement my casting with. I just reached level 6, and I'm trying to figure out which spell to memorize next. I'm looking at Stone Arrow, Lee's Rapid Deconstruction, and Summon Elemental. I've got two points in spellcasting, three points in transmutation (on the cusp of becoming 4), and seven in Earth magic. I've got Sandblast and Stoneskin memorized.
My first thought was to get Stone Arrow, but Sandblast has been serving me remarkably well. I've got 80+ stones that I'm working off of right now, and I'm at the point where I can nuke a giant gecko or sometimes a hobgoblin in one go (which is good, because I've only got two tiles of range). I'm wondering if it's still worth picking that over the other options at the moment.
I have absolutely no experience with Lee's Deconstruction, but the description seems to indicate that it might be of assistance against certain statues or other monsters later on. And from what I can gather, it basically serves as a grenade explosion for whenever you're near a wall (which is most of the time).
It was my intention to delve into elemental summoning at some point, and my wiki research seems to indicate that I currently have a 100% chance of summoning a friendly earth elemental, which, y'know, is nice. However, I haven't got any skill in summoning and the spell looks to be rather difficult to cast.
Any recommendations? I've also got Passwall in this book, but I figured that it probably wasn't going to help me as much as the others.