A few huge emails can rapidly overtake your inbox. Unfortunately, Gmail doesn't give us a way to filter email by size but a new service appropriately titled Find Big Mail does.
Find Big Mail is a freemium service and does have a free trial. I paid $4.95 for the single account but it was worth every bit. You can find them at findbigmail.com.
Run the service on your Gmail account of choice and get a nice report, via email, that tells you how many emails you have by size broken down as follows:
-10MB and larger -5 - 10 MB -1 - 5 MB
The report will even include links that allow you to filter through those messages and start eliminating at will.
For full details, check out geekbeat.tv/tip16