Because I usually don't use a spotter, I use the dumbbells to bench... I just got back into working out last week, and had to use two 20lb dumbbells to get back into it. This was pretty low weight (total of 40lbs) and the combination of that and the fact that dumbbells require you to balance each side gives me (personally) the 'illusion' that the lower weight is ok to use. Thus, I don't feel any guilt or need to move higher too quickly.
Remember - it's not the amount of weight your pushing, it's the fight on the last rep (or two or three) that makes the difference. A lot of bodybuilders, instead of adding weight to their sets, will instead use superslow repetitions and greater concentration on the the flexion at the end of the rep. Use the same weight, count to 4 as you push out your bench, squeeze your chest muscles at the top for a count of 2, and then count to 8 on the way back down. Now, tell me if that doesn't feel different, and you will definitely feel more fullfulled.
...oh, and don't forget that the last rep should feel near impossible to push out. You should be able to push halfway, have to fight it, and keep trying to get that weight up until you can't move it out. If you keep fighting for up to a count of 10, bring the weight back down, and (possibly) try it again for a final 'impossible' rep.
I guess what I'm getting at is that good form and a good slow speed will always outweigh (ha!) extra weight and fast, jarring movement.