At a big, established company, you have meeting rooms. Some of them are very elaborate and full of sophisticated tools (toys).
At a startup, you don't have the luxury of having a fancy office with great meeting places. In fact, here's my current office. So as a startup, I've had to find other places to meet. And I have, of course, started using the often used coffee shop. I started meeting at Starbucks. But I'm not a fan of them. Most Starbucks are small and do not allow you to find a corner or nook at which to meet with people and have it feel somewhat intimate/private. At most Starbucks (there are exceptions), you are close in with others and it does not feel personal. So for coffee shops, I've found the locally owned ones to be much better. You have to do some research to find the good ones. But they will be larger than (most) Starbucks. They'll have spaces that are more divided. And the food/drinks are usually better. An example of a great local coffee shop is Cafe 976 in my neighborhood of Pacific Beach. It's only 3 blocks away from me, which is one block farther than the nearest Starbucks. It's a converted house, so there are lots of spaces tucked in random corners where you and your meeting can have a (semi)private conversation. I'm now working on collecting a list of similar types of local coffee shops in all the major neighborhoods in San Diego. So no matter, where I want to meet, I'll have a good venue.
Sometimes I don't need to meet with others. But I just need a place to sit down and work. My only needs are a space to sit and wireless access. One place I use for this is McDonald's. Seriously! They have WiFi access at all of their locations. I have seen a sign at one location (SeaTac, WA) that said guests were limited to one hour. But I have worked at one for over four hours. I find that I'm not the only 'squatting' there. Usually, there are a few seniors too. Definitely less Macs than Starbucks.
And another option that has a better aesthetic is to work in a hotel lobby. You can read more about that in this WSJ article.
So my startup friends, save money on offices and conference rooms. Instead, leverage public spaces.