I've been on several giraffe "hunts" just as a back up gun, but like some others, I never had a particular interest in shooting one myself as a trophy. They just always reminded me of "Melman" from the Disney cartoon. I did shoot an old cull "stink bull" last year in Botswana. He truly was on his "last legs" so to speak. He was an old bachelor that Gerhard knew had been kicked out of his small herd a few months earlier and was still healing from battle damage. We were able to close to within 100m on the old boy and could see that he was absolutely covered in ticks from his anus all the way under/between his legs and underbelly all the way over his penal sheath. Sure sign an animal, any animal is in serous decline. Once he was down, his teeth were pretty much gone as well. He still had not lost much muscle but it was inevitable and was at the perfect time to taken as a cull.
Giraffe hunts can be really challenging on foot. For one, they always have the high ground. Second, they really do camouflage well in the tall acacia thorn trees. Their legs actually blend in well with the tree trunks and their bodies are up high and well covered/protected by the tree vegetation. Sometimes the only thing you can see/look for are their heads and it is so unusual to have to look UP to spot them as well as DOWN to make sure you're not bumping other game that might alert them. And as I mentioned, they always have the high ground.
As Castnblast mentioned, their hide and underlying protective tissue is astonishingly thick. Has to be when you see them running full tilt thru the thorn trees like there is nothing there. The hide/tissue from maybe the middle of their rib cage forward and up can be as much as 4" thick. The hide/tissue at the rump/hind quarters is thick as well to protect them from the head/horn blows when they fight. This is also one reason their vital organs are farther forward and up higher in the chest cavity. That thick hide/tissue is one reason the tanning process can be kind of pricey. A LOT of de-fleshing has to be done before the tanning can even begin.
Caliber/bullets - that thick hide/tissue in combination of the large chest cavity means you really have to have a combo that will drive deep. A 375 with 270gr TSX will get the bullet to the vitals while a 375 mono-metal solid will completely pass thru broadside. I've seen three taken with 375 H&H with 270 and 300gr TSX that got to the vitals but didn't pass thru. I used a 375 Ruger with 300gr, CEB solids and did pass thru. A 9.3x62 was mentioned above and would likely work as well but I would have to recommend a mono-metal solid. That hide/skin is no joke.
Common trophies from giraffe are flat rugs, head mounts, European head mounts and even full shoulder mounts. The leg bones are extremely dense and prized for knife or handgun scales. Gerhard offered to give me the leg bones or skull if I wanted them for free but, I declined his gracious offer as I had taken the animal as a cull.
All that said above, I don't know if I will shoot another. I know personally, I won't take one as a "trophy" but, IF a similar animal in a similar state of decline and facing a protracted and suffering end (no predators in the area), I probably would. As in this case the meat was fully recovered and all the remaining parts were utilized to some economic benefit and it was a challenging hunt.
