It depends on your goals. If you choose your oils well with a total coming almost all from mono and poly unsaturates and a care to providing maybe a gram of Omega-3 type oils then 10% of calories or slightly lower wouldn't be too low...just hard to do. Some people who are bent on restoring cardiac health do this reguarly.
For weight loss and a lifetime plan, a plan of 20-30% fat (by calories) is reasonable and not too hard to do <easy to type anyway
>. Try to limit saturated fats to a third or less of the total and eliminate all hydrogenated (trans) oils.
A lot depends on the kind of food you like and if you are comfy with lower fat go for it.
Some people on the Atkins' type regimens are comfy with a 70% fat diet...not for me!