Sure I leave my browser running all the time. FF runs from a few minutes after I log in until Windows gets flaky and slow weeks-to-months later. Browser tabs are a great to-do list, with context and history. Why would I ever close my browser? 5 seconds to load it up (or 3 minutes, if it's restoring my ~100 tabs) is a waste of time, and RAM is cheap.
It was pity stayed his hand. "Pity I don't have any more bullets," thought Frito. -- _Bored_of_the_Rings_, a Harvard Lampoon parody of Tolkein