For those who don't know, the Ishtar is a gallente drone-boat HAC that starts with some kin/therm resists. It's good against guristas because they do kin/therm damage and target jam constantly (hence, it's nice for drones to be doing most of the work).
I've included two fittings here. One is optimized for resists (the deadspace mods are actually pretty cheap) and the other is a solo scanner/plex runner. Both are currently set up with caldari heavy drones, which should be best against guristas resists even though gallente do slightly more damage. The DPS tank is calculated using a 50% kin, 50% therm EFT damage profile.
EDIT: On the first fitting below, it might be good to replace the thermal passive resist mod with an energized adaptive nano membrane -- as it is, that fit can't tank the EM smartbomb in guristas military complex without taking hull damage, even starting with full shield.
Cap stable and tanking
(note that there is a second ship off-screen doing DPS to the target;
I don't think I could break its' tank solo with my drone skills)
There are two things I've noticed flying the ishtar. First, heavy drones are actually very effective against small rats, at least once they've caught up to them, so once everything's aggressed you can just launch heavies and do something else while keeping an eye on local. Second, the ishtar is completely and utterly screwed by neuts -- some plex (pith penal colony seems to) and ladar sites (h-pa crash crew) have some energy neutralizing going on. In both cases the trick is to stay outside of neut range (about 45 km for guristas energy neutralizing sentries).
EDIT: In response to comments on this post I've made a follow up post addressing shield ishtar setups.