Hmm, three of the ball parks I've been to no longer exist (old Comisky in the 70's and Fulton County Stadium - the one before the Braves last stadium in the late 80's, the Kingdome in the 90's.)
Looking at Interbret's post I've been to a couple minor league stadiums. I like the Tacoma Rainier's stadium but I think I liked the former Binghamton Bees stadium (now they are called the Rumble Ponies - those poor guys.)
So that leaves me with the Rockies Coors Field which I was at in April. I liked it, great site lines, good seats. Eh food and drink especially if you need a special diet. But it reminded me of a lesser Safeco Field (which opened later.)
Excuse the excessive detail below. The Cubs should be coming back to town in the next year or two so I thought it might be useful.
Safeco is my favorite, probably because I worked on the project and know a lot more about the details of the design and how it came to be. I worked for the county and later for the Public Facilities District that built the stadium. The Board and the project manager were all baseball fans and wanted to get the fan experience right. So they toured stadiums that did it right - I know Wrigley was one and Camden Yards, Coors might have been one. They also toured stadiums generally considered to have gotten things wrong. (I've conveniently forgotten those.)
As a result there was a lot of good, intentional choices made. They didn't want a lot of pillars obstructing site lines to the field. Even if a fan was waiting in line for food they wanted the fans to be able to see the game. There are a lot of televisions placed around the stadium too, to help you see everything. They wanted home runs to be possible because Griffey was on the team while design was going on (it opened in July of 1999.) They rearranged the seats on the right fowl line in the outfield to give fans a better view of the game by angling them toward home plate. This created the little odd corner in right field they hoped would become a feature the Mariners could play better than the opposition (I don't think it turned out that way.)
If you go to Safeco, stop in at Edgar's Cantina. It is next to the bull pen and there are peep holes cut into the wall adjacent to the bull pen so you can see over the catcher's shoulder and get an idea what it would be like to face a major league pitcher.
There aren't any rainouts thanks to the ridiculously expensive retractible roof the public paid for (the stadium cost over $400 million if I recall, huge cost over runs because of the tight building site next to the train tracks that are a primary shipping line for the west coast, and the need to hit the deadline so it could open after the All Star break.) They had a design competition for the retractible roof. One solution was to float it on a trough of water. Getting permission to retract the roof over the train tracks was tough. (So anytime someone talks about building a roof over a stadium that is fenced in with roads, just know it's not cheap or easy.) There are rules for when they can open and close it so as not to interrupt the game, they do open and close it though during games which is nice - if the sun comes out the roof comes off.
Food is done right. There are a lot of choices from standard ball park fare to more exotic choices. I do think the grasshoppers (cooked grasshoppers, not the drink) were overkill. Dairy free, gluten free, vegan, they even have gluten free beer on tap from a local gluten free brewery Ghost Fish. There are also nearby restaurants, breweries and bars. There's a Safeco Foodie Twitter account if anyone is interested in that.
Public transportation has improved greatly. Since Safeco opened a new light rail line was put in that drops off next to Safeco. The express buses from Tacoma and elsewhere also drop off next to Safeco on a protected road so the buses don't get caught up in the rest of traffic. The buses from Tacoma are the luxury type with high backs, wifi and free parking in Tacoma making it a no-brainer to take the bus in. From the drop off for the buses and light rail there is a ramp that goes over street traffic so you don't have herds of people waiting for lights to change or mixing with street traffic. If you drive there are parking lots but you will get caught in traffic and may have to cross busy intersections.
Lots of touristy things to do in the NW. Theo chocolate factory in Fremont gives out free chocolate samples in their store and it is just a couple of blocks from the Fremont Troll (look it up.) Whale watching is a must do. They have a radio network so it is rare they don't spot any killer whales. I've always seen lots on the trips. Mt. St. Helens is worth the trip to see the destruction that is still visible. Really changes your perspective of nature. Mt. Rainier is usually good for a summertime snowball fight in shorts. There are ferries up to Victoria Canada too, but you need a passport to go there.
Ok, I've wasted enough time.