I'm from Germany, so I can't say which exact detergents to get, but from experience, one needs at least 3 products:
1. Detergent without any bleaching content. Will keep your laundry look like new and reduce fadeing. Can be hard to find, though. In the EU, liquid detergents do not contain bleaching agents and only small amounts of brightners. However, the US has liquid detergents that do contain bleach. There, its one trip to store and just looking through the labels.
2. A detergent with bleaching agents or some kind of bleaching additive. Use it on whites or resistent, heavy soiled colors. Whites won't turn dull, and certain stains just are best "removed" by bleaching.
3. A detergent for delicates, specials and wools. Usually, a detergent labeled for wool covers this branch. I use it for stuff like synthetic blankets, some more delicate items, wool sweaters and outdoor wear. This stuff usually does not contain enzymes due to wool being a natural fiber, but therefor other contents. Some of them suds up a tad more.
As "Add-Ons", depending on what you find you might need:
-Something to pretreat heavy stains if its just one or two heavy spots in a otherwise average load.
-Softner: I find it rather useless if laundry is dried in a dryer, but some just like the added softness. Though, again, there is debate if softner use might aid in the mold\smell issue. A good alternative are dryer sheets, which usually give better smell while reducing the washer smell problem.
-There are some special detergents out there. Some find them awesome, some plain gimmicky. We only have one extra detergent, which is a detergent specially designed for curtains (high oxigen bleach content, high sudsing). This, again, is up to what you think you need.
Powder versus liquid has been a debate on its own. Some manufacturers service departments (Miele for example here in Germany) recomend powder due to residues clogging smaller vent hoses in their drain system, but some like Samsung over here warned to use powder due to it not complety dissolving.
Some like the dosing of liquids more, some that of powder.
In the end, I guess its a draw. Use primarly hot and warm washes to make sure stuff gets dissolved, don't overdose, don't underdose.