Used to be the best bargain area in the world. No more.
Akihabara is a tourist trap. I think I caught it in the last of it's glory days (late 90's) before the internet killed it, an the maid cafes took away what very little of Geek Chic it had left. The only deals to be had are on the internet, which is where kakaku.com comes in.
Average salaries are comparable to U.S. However, in Japan most employees have two bonuses per year that can increase basic salary.
This is a tricky one, and just like most things in Japan, it's pretty complicated. The salary is generally inclusive of bonus, just worded differently. I would say starting salaries are similar to the US. From there, it's a turtle race. Japan, for the most part, still employs a seniority-based pay scale. So, despite how hard you suck, you will likely get a 10,000 yen a month raise each year. Your bonus will always be the same relative amount of your salary... it's not performance based (most of the time). The starting salaries for those living in Tokyo is abysmal. Painfully hard to make ends meet, and new levels of frugality are set. There are some westernized countries which let you eat what you kill. Rakuten comes to mind. But these are few and far between, and until Japan hits rock bottom, I doubt we will see any employment trends changing.
The deflation issue is a difficult one. The country has been deflating for 20 years, yet there is more doom and gloom on the street. This could be for any number of reasons (higher unemployment, for starters) but is beyond the scope of this thread.
They also are now subject to a VAT on all purchases, and import duties for foreign products is VERY HIGH.
It's actually very low, depending on whom you're comparing it to. If you get tagged at all, it's 5%. That's high compared to the US where things fly under the radar almost all the time. However, most of the time they go unnoticed. The only time I've ever had to pay is on very expensive items. $2k USD and up. You can bring with you 200,000 yen of personal items when travelling, without having to pay a duty. Local sales tax is 5%, but the big news is the hike to 10% over the next few years, to pay for the tsunami.