You can easily disable auto fetch on the client software (For example, Microsoft Outlook) you are using.
If you want more freedom with the email settings then go with paid email services since free email accounts won't be of much help for you when it comes for custom settings.
Well I've used lots of webmails, including Yahoo! Mail and Hotmail but until now none compare to GMail. For me it is definitely the best. It's fast and easy to use. Yahoo! takes so much to load an email and when I'm in a hurry I feel like cursing all the time because of it.
I prefer to use Yahoo email service in past due to its simplicity in Yahoo Classic version i like that version, but now thinking to move to hotmail because yahoo has automatically upgrading to the new mail version.