If you're the type of guy who has an "I don't care" attitude about clothing, but you're not at the point yet where you mean that literally, there is a wardrobe for you that will involve the least amount of effort.
Keep It Simple Stupid
If you don't want to spend more than a few seconds picking out your clothes everyday, keep it simple by ensuring that every single item in your closet matches everything else. When buying clothing, stick to neutrals and solid colors. Bottoms in black, khaki, and jean for example, will match any color of the rainbow top, but just to further simplify it, stick to a color pallette of 4 colors like white, black, blue, and red for your tops and buy all your tops in those mainly solid colors with a few patterns thrown in. This will ensure that without even trying, you will automatically be able to pick any top and bottom in your closet, and they will look good together. This will also help you with packing for trips and vacations because say, you stain one shirt, literally everything else in your suitcase will go with everything else.
Get rid of the excess
If you are under the illusion that you need 100 pieces of clothing to look like the guy that looks good on the street or in a magazine, you're wrong on that one. Head to your closet and ditch anything that doesn't fit, that still has a tag on it, that's outdated or that's got stains/rips/bleach on it. Part of having so many clothes in your closet, is that you have to spend that much more time rummaging through it trying to find something that works. You can pare down your wardrobe as above, by keeping it simple, and by overall limiting the amount of choice you do have. If you don't feel good in it or it's damaged, toss it or donate it.
Shop for the real you
If your job is doing construction all day, every day, odds are, you don't need to own 4 different tuxedos. Conversely, if you work in a corporate office, you are going to need far more suits than you do shorts and flip flops. Focus on creating a functional wardrobe that is based on who you really are and don't buy items that will remain in your closet forever because you think it looks cool on someone else or you're buying for a lifestyle you don't actually have. This is a closet space, time, and money waster.
Buy what works in bulk
If you try something on, and it feels and looks amazing on you, and the color is great, the size and length are perfect, and it's a good price, buy it in bulk in more than one color. This is an actual item you will get use out of and will save you time with having to try on a bunch of other stuff that doesn't work in the future.
Invest in at least one nice black suit
A black suit will take you everywhere from an interview, to a date, to a funeral, to a wedding. This is one of the few clothing items I would ever suggest to anyone to spend decent money on so that you can get the most wear out of it, especially if you are the type of guy who doesn't have to dress up a lot. You just really need one good solid suit to get you through the year.
What Guys Said
I wear jeans, black rock/punk/metal band shirts, biker boots, sunglasses, and cafe racer jackets or a pea coat. The look works for me. (Although I do have a black suit, that I wear without a tie.)