The city of Gilgit is impressive, but then again not so impressive. It is a big city, with restaurants, houses, hotels, etc but has no major attraction. However, it has benefited from the beauty of its northern counterparts. People usually stay here a lot. It can get very good in Gilgit, upto 40 Celsius is normal in summers. There is little greenery, its hot, sweaty and pretty unimpressive. If a tourist comes from, say, with all due respect, Holland, and he has not seen anything higher than 500 m in his life, he will be stunned by Gilgit and its beauty. However, if have been in such areas before, I wouldn't advise Gilgit too much. The only attraction in Gilgit is perhaps its suspension bridge over the River Indus, which is the largest in Asia. There are also a few Buddha carving and statues nearby so take a visit there also.
Unique Suggestions: Take a good room in a hotel with Air conditioning (in summers) and hot and cold water. Mosquitoes can swarm in on days of slightly cooler weather.
Fun Alternatives: The valley of Karimabad in my eyes is a better option than Gilgit.
PS: Karimabad is the administrative capital of the Hunza Valley.