I prefer the regeneration. That's not to say that health packs don't have their place, it's a design choice that will depend on the game. In Half-Life, for example, the health packs encourage exploration and in Fallout, healing yourself is part of the whole "survival" process that makes the game compelling. However, in most shooters I find that the regeneration system works well to keep the action going whilst constantly giving you a sense of peril. I remember playing health-pack paradigm games where you would get down to really low health and have to wander around really slowly because one shot would kill you. Whilst that's kind of exciting, it's also very frustrating and more often than not you lose a lot of progress as a result of actually playing rather well. Like I said though, it depends on the focus of the game. I think regen is best for action-heavy games whilst survival games should favour the health pack. I don't think we should get stuck in one way or the other.