I think the average savings rate is about 5%. Rajasekhara suggests 20-25% would be ample, but he subtracts some things. I'd suggest you try for 10-15% without subtracting anything. Either of these will work; just be consistent. If you're not where you want to be, compute where you are now. Then increase 1% per year till you're where you need to be. Good luck.
ADDED LATER: I just realized I didn't answer your question. I save 15%.
Any savings in the range of 20-25% of your Gross income should be considered as good amount. This is what I too follow. But if you have monthly EMI's for home loan then it can be less as this EMI can be counted against savings ( Do not include other EMI's like personal loans, car loans etc).,
It depends whether i'm doing a lot of shopping or not , but i have 500$-1000$ savings minimum each month :)
$500-$1000
