As Evil Overlord, you have a great need in maintaining armed forces. These troops will be used for invading other countries and subsequently taking them over. These troops will also be used for protecting conquests already won. They will serve as a backup to your other local law enforcements. Theses troops will also be protecting you own sorry butt.
You want these troops in top shape. They need to be healthy. They need full competency in all forms of weaponry, primitive and advanced. Competency includes knowledge in the use of, and in defending from every weapon ever known to man. Hopefully this knowledge will be paramount in fighting off the Ewok uprising which is bound to happen sooner or later.
With the troops trained in this manner, they should be able to construct their own weapons at any given moment. This makes arming them a much simpler matter. Instead of having to come up with an elaborate array of weapons, a simple standard issue pack can be used for each soldier. This pack should include a semi automatic handgun with a caliber bigger than 9mm. You should probably make this a standard to save cost on ammunition, as well as easing the burden of the supply chain. I would recommend a 45. Each soldier should also have an assault rifle. Again make this a standard rifle and round. Those who have proven efficiency at marksmanship, may exchange the assault rifle for a sniper rifle. This pack should also include a good knife or two, and a few hand grenades or other portable explosive devices.
This is all general issue. If the need arises for something different, something a little bigger, this must be provided. Do not worry about what may be required. Your troops will inform you soon enough.
Although in most fighting groups there is one designated communications officer, every soldier should be equipped with his own radio and locating signal. This is for obvious reasons. If I must spell this one out for you, you are too incompetent to continue pursuing the Evil Overlord position.
Body armor is a necessity, but must be tailored to the position being patrolled. While in the navy serving on a ship, body armor is not going to be of any use. While patrolling the streets of occupied france, light armor will be required. While leaving your tent to go to the can in Iraq, heavy armor is a must.
If you have trained your men properly and given them the tools necessary, your troops will be able to look after themselves, and be able to provide you with the greatest military force ever assembled.