An understanding that this is an area of ongoing research will go a long way. also realise that much of the stuff we were told as kids is just wrong.
because the clinical answer doesn't really give you the true picture of the effects a regularuser experiences, I'm going to use myself and others I know as examples in answering your question.
Short term: relaxation, talkativeness, reduced attention span for some, increased creativity and problem solving (for me personally, I know this is not true for some. The test is, is it still a good idea when you sober up 
), falling asleep, things taste, look and smell better, video games are more fun (I'm better at them when high), stuff is funny...
Things that are not true for me or the people I know at least: Problems with memory and learning, I learn new stuff high all the time and remember it just fine thank you. Decreased motor skills, this is true for a new smoker. However once you become experienced this effect is greatlydiminished. Do you think so many athletes would smoke weed before preforming if this was the case?
Long term effects: more peaceful outlook on life, less money (weed is alot of $$$, BUT weed will get you though times of no money better than money will get you though times of no pot. believe me.), maybe my short term memory is worse by a bit, but it's hard to tell because they told me I had problems with that all throughout school. Before I had ever even seen weed.
Things that aren't true: "Marijuana smoke contains some of the same cancer-causing compounds as tobacco". That is true but, marijuana also contains many anti-cancer components and studies from this century find no increased long term risk for lung or head and neck cancers from cannabis. "Weed will make you CrAzY". If you are already predisposed to that, yep it might. But that go's for any drug. Bottom line, if you have mental issues you better think twice about any drug, legal or not.
Cannabis is a mild psychedelic and as such your attitude and expectations do play a part in what kind of role weed can play in your life. The more you learn about and understand this wonderful plant the better it can assume a helpful role in your life.
