I did a bunch of research on this a few months ago. It really depends what your primary usage for the gi will be: intense training (as in, trying to make the cardio part harder on yourself, e.g. by wearing a thicker gi), regular training, or competition. Mostly, the names change, but there are just a few types. Ripstop is the lightest and a lot of people love it, but has recently been banned from most major competitions, so only buy these for regular training purposes. Then there is single weave, which I feel is the best option generally. It is lighter than average for weigh ins, but still thick enough for good training. Especially if you live in a hot area, and if you train a lot, I feel like single weave is all the sweating I need to do, and it helps for weigh ins as well. At the other end of the spectrum is the "thick" gi, often called gold weave, double weave, pearl weave, full weave, etc. For some companies, a gold weave might only be as thick as another's single weave, while for others, the thicker model can feel like an 80-lb wool blanket. So, you also have to consider the company you are choosing.
Here are my personal favorites of the options I have found:
OUANO LIGHTWEIGHT GI - My favorite gi. Easily thick enough for any purpose, but reasonably light. The pants are the best in the business, and the company simply makes amazing gis. Also, their customer service is awesome, and they only charge $30 to completely customize every single dimension to your body. I paid about $160, including shipping, for a roughly A2 sized custom lightweight gi from them, and in the future, they will keep my dimensions stored for further orders. I suggest everyone buy this gi.
BREAK POINT DELUXE GI - The BP Deluxe is about as thick as the Ouano LW, so don't worry on that front. BP is a newer company that has really tried to rethink the whole gi-making process. I imagine in a few years they are going to really start taking over with new innovations. In the meantime, the gis are pretty good, and they took off the insane amount of patches that used to come standard and drive me crazy. Here's the other main factor - while they are pretty affordable, each set comes with 2 different pants - an extremely light, competition-legal ripstop pair for tournaments (SO nice to have), and a very thick, gi-top material pair for heavy training. It's like having a training gi and a competition gi in one. My second favorite gi.
ATAMA GOLD WEAVE - I don't have one of these, but they are the industry standard for excellence. They are durable as hell, and just generally well made. If you want a heavier gi to train in, or you roll like a maniac and dont want to rip your gear, this is the one to go to. The main downside - Atama is a known name in the business, and so their gis are pretty pricey.
GAMENESS - Again, I don't have one, so this is second-hand information. However, I have heard the Gameness is great if you want a cheap spare gi. They are shockingly cheap, but made pretty well. I have heard, though, that the top seems to be built to favor a shorter, stockier fighter with a barrel chest.