That's a good point MerricB. Really, I actually rather enjoyed WulfRatbane's threads about the sweet spot in D&D. This is just an adjunct to that idea. If you enjoy a certain style of play, then stick within the level range that applies. Otherwise, it will very quickly become very frustrating.
In other words, if you want to keep things low key, heroic fantasy, then single digit levels will likely fit your mold rather well. Add in the odd double digit NPC and Bob's your mother's brother.
OTOH, if you want to do something different, say planar adventures or Dark Sun, or even Scarred Lands which is a fairly high octane setting, then bumping the level curve upwards a bit might fit better.