I've always loved trolls in Shadowrun. They're big, they're tough, they're in your face, and it isn't always fun to be the big man on the block. When you can't solve all your problems through violence and intimidation, all the violence and intimidation others think you're capable of works against you. So trolls would end up being far more anti-social on average than every other metatype. Their size alone makes them quite literally a poor fit for sixth world society. One of the things that always stuck me are the manifold problems for trolls in the sixth world.
They need to eat more, their clothing costs more, the vehicles they can fit into are more expensive, and they are the smallest minority of the five metatypes. The first three make everything about their lives more difficult and expensive, and the last can make it very hard to find someone who understands you, and can safely and comfortably have sexual relations with you (I think about this stuff too much...)
For giants, the problems are even worse. Though they are more human in porportion, and less "ugly", they are even bigger than other troll metavariants. If you were 3 meters tall, I have to admit, there would be desperately few chances for you to make a life for yourself in the sixth world in a legitimate fashion. You would scare the hell out of people all day since you tower over everyone, even trolls. Less ugly, but seemingly more inhuman. And you just don't fit in; clothes are hard to find, food is going to be a problem, and just living indoors is going to be a struggle. What apartment in the sprawl has ceilings to fit you? None. The best thing I could think of for a giant in the big city would be to squat in or rent out a loft in a warehouse (one that hasn't been converted too much, so it's not a warren of tiny tenements), which would be the only place I would think you could comfortably stand up.
As a runner, I don't know how well you could do. You would really stick out, and be memorable. Equipment will be even harder to get in the proper sizes. How easily can you fit into corp labs, warehouses, etc to do your job? You'd have to crawl through doorways. You'd get damn sick of sitting cross legged in a bar for a meet with Mr. Johnson all the time. It must suck to be a giant, and I feel for the fictional fellows. Your sort of destined for either finding some kind of niche in security or construction, somewhere your size helps, or being a squatter or neo-primitivist, leaving out in the wilderness. A gang banger life is one of the few places you'd fit in relatively well, even then, you'd be lonely.
I think giants would try to live a full immersion lifestyle often, escaping into the Matrix to be in a place that doesn't judge them by their size and appearance, a place they do fit in. I think metatype and metavariant dating services and social networks would be vital for many metatypes, to find the right kind of mate who is biologically compatible, as well as emotionally and intellectually. I know they like to push the transhumanist nature of sexuality in the sixth world, with all kinds of doodads to let trolls and dwarves do the nasty safely and with lots of fun, but I think when looking for companionship, a giant would want to find another giant, a relatively rare metatype to find at all. Long distance and virtual romances to find someone who fits you would be something a giant would have to deal with.
One thing that I think is cool is Evo's Metaergonomics brand, building consumer products for all peoples. I remember in an old SR2e adventure there was a part of the run that involved kidnapping a troll whose family owned a store that sold troll sized gear, including motorcycles. I saw the bike that Jesse James built for Shaq, built to his specifications. It was a monster bike, and when Shaq got on it, he said it was the first time in his life he felt small. The bike, unlike everything else, was built to fit him completely, and it did. I can see a lot of giants going for similar custom bikes. It would be a form of transportation you could get relatively cheaply custom made for a giant's size. It would also be huge and awesome. I think a bike made for a giant would outweigh most cars on the road in 2072.