Depends on what's in it.
I see scores in the six digits I look to see what sort of things they've achieved and in which games. A quick once-over will reveal if the player is someone that actually attempts to genuinely play well, or if they're just in it for the fast and easy crap.
Look at a gamertag like an empty bucket. Sure we can drop whatever we want to make it look fuller than someone else's, but in doing that are you filling it with turds (Avatar, most sports games, etc) or with gems (Mirror's Edge, Modern Warfare, Hexic HD). Your bucket may runneth over, but if it's all shit, who cares?
Personally, for me a gamerscore appeals to only two real things that were there long before the Xbox 360 was ever made. I'm a completest; I spend weeks looking for hidden packages, days trying to find that last hidden object, or to learn a stage in a shooter so well I could complete it without thinking and in record rime. Gamerscores also, in a way, help to justify what I was already doing to a minute but tangible degree.
It's not the size, but what's in it that counts. I just hope that whatever system they decide on the next time is better constructed to reward good play and not simple grinding or button mashing.