Photek's got a point, some of the hordes of splicers you fight off in the later game can be great fun, because of the opportunities to scope out an area beforehand, lay traps, exploit the environment, and so on. I can still clearly remember defending a Little Sister in one room that had two entrances, from a corridor that ran around the outside. I'd hacked a couple of sentry bots, laid traps, and there was oil on the floor somewhere, so when she started harvesting, all hell broke loose. Tons of splicers hurling themselves headlong into traps, fire, and bullets, whilst I largely got to sit back and watch, polishing off the odd one that got through. Just after it all triggers, there was a jukebox in the room that sparked into life, playing "How much is that doggie in the window?" as all this chaos was going on.
Genuinely brilliant moment.