Lenin

I think the ARB's and the diuretics are the easiest, side-effectswise. THe diuretics are the stronger drugs IF you are the proper "type" of diabetic. The ARB's are weaker but work well with some addition of thiazide diuretics.
A very good class is the ACE inhibitors which are excellent for those people who don't get a never-ending cough from them. THey are also cheaper than the ARB's which work in a related way. Try an ACEI first; if you cough go the ARB route.

THen there are the calcium channel blockers; weak and rather hard for some people to take: they differ among themselves a lot, so trial and error might be the way to proceed. They usually need a second drug (like thiazides) to get satisfactory control.
Beta blockers are powerful, cheap, and full of side effects like fatigue, bradycardia, insomnia.

There are also a few drugs that are specialized like MAOI inhibitors, alpha-blockers, clonidine and sedatives....I presume for people who have severe, malignant hypertension. I'm not really up on any of them.