I find gladioli so majestic with glorious colours. A tall vase of gladioli always look magnificent.
My mum and I have both grown gerberas over the years and as they have developed them, they have become much larger. I particularly love the yellow ones.
Gardenias I love for their perfume and their whiteness, although the creamy ones are also beautiful. (I remember as a teenager going to a tennis club dance with a friend. During intermission we sat with our boyfriends in a car just outside. June and I both had gardenias in our hair and with the windows closed the scent of the gardenias was overpowering. It was a wet night so we went back into the hall as we couldn't, of course, wind the car windows down.)
As for geraniums, I love them and have always had some growing either in my garden or in pots over the years. They are so easy to grow as pieces that drop off will take root very quickly. I currently have a beautiful dark pink one in flower as well as a paler pink and some reds. The dark pink bush is about 3 feet high and has grown from a slip I stole from a bush at the local school several years again when we went to vote in one election or another. I am sure it was never missed as it was only a tiny slip. (Is my guilt showing there perhaps?)
Which is your favourite "G" flower? I didn't mention gloxinia which are also beautiful. My dad used to grow them in his glass house but I don't regard them so much as a 'garden' flower.