Latex or Oil-Base Paint

Latex paints have been improved a great deal since they first became popular in the 1960's. Some modern latex paints are actually better than oil based paints for home interior and exterior surfaces. It's important to choose the right kind of paint for your job.

Flat Latex Paint is fine for interior walls and hides surface irregularities well. Some brands offer one for walls and one for ceilings, but I always use wall paint. Can be cleaned, but in high traffic areas, and in kitchens and bathrooms, use Semi-Gloss Latex Enamel.
Semi-Gloss Latex Enamel is fine for trim, cabinets, laundry room, bathroom, kitchen, kid's rooms, and anywhere that a semi-gloss finish is wanted. It is very scrabble, and somewhat water-resistant.
Acrylic Latex Paint is designed for exterior use and comes in flat, semi-gloss, and high-gloss finishes. One of the benefits of using latex outdoors is that it is more flexible and "moves" as the surface heats and cools, instead of cracking or blistering.
Primers made for interior or exterior use are available in latex and oil. When painting over oil paint, oil primers work well with latex paint. If you're painting metal, after sanding, wipe with turpentine and apply an oil primer before painting with latex. For new work, use latex primer and paint.
Oil-Based Paint no longer has lead. The vehicle is usually linseed oil and turpentine, with other chemicals and coloring. For special applications, oil paint is great. For example, to get a flawless finish on a door, gloss oil paint with a small amount of linseed oil added will leave a mirror-smooth finish if applied properly.
Stains:
True stains are designed to stain the wood to add color. Other types of stains are more like paint -- they let the texture of wood show through, and sometimes let some of the wood color show through, but usually provide less protection than paint.
Often doors, trim, and furniture are given a true wood finish by using a true stain. The stain is applied then rubbed off to leave only the softer grains colored, finishing with a sealer like varnish or polyurethane.
Varnish & Polyurethane:
These are similar in what they do but are made of very different materials. Varnish tends to yellow and is not as long lasting as polyurethane. Where I live, you can't even buy varnish anymore. These come in satin and gloss finishes. Polyurethane also comes in a high gloss finish that looks like glass when several layers are applied. Not for outdoor use.
Shellac:
This is an alcohol-based paint or sealer. It is seldom used in homes, but I mention it here because it makes a good primer for plaster that has had water damage and a brownish discoloring is bleeding through. It also helps stop light crumbling of plaster.
KILZ -- Special Primer:
This helps cover stubborn stains, grease, graffiti, plaster stains, and other problem surfaces. Used before primer and paint, this will cover almost every kind of stain that bleeds through.
Epoxy Paint:
This is a very special paint used for extreme durability and waterproofing. It is two-part paint -- one can have the pigment and vehicle and the other can have the catalyst and hardener. After mixing, it must be used within eight hours. Sometimes, this time can be extended if refrigerated below 40 (f) degrees. Very scrabble and works well in showers and around pools. Extremely hazardous to use without proper ventilation and/or breathing device.