Online Stores
Jpophelp is my favorite website for buying Japanese magazines. They also have an awesome collection of CDs and dvds for sale. They process orders very quickly and shipment to the US isn't that expensive either. The only problem is that some of thir CDs and magazines aren't always instock... but you can decide for yourself whether or not your willing to wait for that special CD or magazine to arrive... Also, be careful, they stock lots of bootleg cds. (made by Ho-Son, ect.) However, for Malice Mizer cds you shouldn't have a problem. You can easily tell if its a bootleg by the price, also. If a dvd is all-region and selling for $15, it's bootleg. If it's $60, it's the original version :). VHS are usually all original. Overall, tons of great magazines, and frequent updates.
Yesasia is probably the biggest Asian entertainment store on the net, they're bound to have just about any major Asian product your looking for... whether it be magazines, cds, books, posters, movies, toys, ect. They do not stock much (if any) indies cds, and it takes quite some time before they sell new jrock cds. This is more for mainstream Asian artists, because most of them have overseas versions of cds, whereas the originals tend to be quite costly. The shipment is a bit more expensive than Jpophelp, but that all depends on where you live. Like CdJapan, Yesasia is also updated almost EVERY day, so it'll always have new products.
Mana
Belle
Jpophouse is a great place to buy some hard-to-find and unique Jpop/rock merchandise as well as cds and dvds. They have a large selection of photobooks, posters, magazines, calendars, photos, and even t-shirts and toys! What's also awesome is that they have a section where they sell rare collectibles, like fanclub magazines, tour goods, and promotional goods! They process orders very quickly, and even better: Shipping (without insurance) to the U.S. is free!! Like Jpophelp, they stock bootleg cds and dvds, but this isn't really a site I'd go to to buy cds anyway, I'd leave that to Jpophelp or Yesasia. This site is definately for those items that you can't seem to find anywhere but on E-bay once in a blue moon!
J-xyz is a great place to buy some hard-to-find and unique jrock merchandise. While they don't have as much as the sites listed above, they make up for that with the goods they offer. From this site you can buy rare promotional posters, lots of fanclub magazines, tons of tour goods, trading cards, buttons and keychains. You can also buy some of the best jrock magazines out there for a low cost. Payment with a credit card must be done through Paypal or Billpoint, but they also accept Bank Draft / International Postal Money Order / Money Order/ and cash. In addition, shipping can be *quite* costly depending on where you live.
Cdjapan is probably one of the largest and most well known Japanese entertainment stores on the net, they most likely have any major Japanese cd and dvd you're looking for. They also have products from a few popular indies bands. In addition, they stock calendars and photobooks. Another great thing about this store is that they list new cds for pre-order, or have them by their release date (you don't need to wait a month and a half before you can order the cd you want ^-^). The shipment is very resonable also. CdJapan is updated very often, so there's always something new.
Fujisan is a huge Japanese store on the net, they have just about any major Japanese  product your looking for... including cds, books, movies, toys, anime, food, clothing, and subscriptions to magazines. One thing that may be a bit confusing is that the website tends to spell things the way the Japanese pronounce them: Malice Mizer's (Marisu Mizeru's) single "Illuminati" is spelt "Iruminatei" o_O. Also they don't seem to split the romanji into separate words: "Kyomu no Naka de no Yuugi" is written as "Kiyomunonakadenoyuugi".The shipment tends to be a bit expensive, but nothing too bad.
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