We're heading to Osaka next month for a few days.  Does anyone have any recommendations on what to do or see?  We're obviously spending a day at Universal Studios.... or 2... but I wanted to know if there's anything there we'll regret not seeing while we're there.  We'll have 4 kids in tow, so whatever it is must be kid-friendly (no late night partying for us )

Thanks in advance for any ideas.

Definitely Osaka Castle! It was beautiful! We just went down for a weekend and went to Universal Studios the first day, and decided to go to the Castle before leaving on Sunday and spent much of the morning/afternoon walking around up there. I wish we had more time to explore while we were in Osaka, I really liked it down there.

Check the picture albums on this website. Then check osaka. I have pictures when I visited.
www.japanbases.com

There's a Kiddie-Land in Osaka that I really want to go to. I think your kids would like that too. XD

Shinsaibashi, America-mura. Crazy teen-fashion meets giant Louis Vuitton, Chanel, and Gucci stores.

How about Suijo Bus (Water bus). There are 4 types of ships but I recommend "AQUA mini" best.
http://suijo-bus.jp/language/english/

Floating Garden Observatory - strange shape building with observation deck.
http://www.kuchu-teien.com/english/

KAIYUKAN Aquarium - one of the largest aquarium in the world.
http://www.kaiyukan.com/language/eng/

Cherry Blossom at Japan Mint - the schedule for 2010 isn't yet announced. It's usually mid April. Why at Mint? I don't know, but the place is very famous for it's cherry blossoms.
http://www.mint.go.jp/eng/sakura/index.html

Crazy baseball experience with Hanshin Tigars fans at Koshien Stadium - one of the old baseball stadium in Japan and famous for its tooooo hot fans.
http://www.hanshin.co.jp/koshien/schedule/schedule201004.html

Okumura,
Good to have you on these boards, as it appears you have plenty of experience that could help alot of us in all different areas.

Hope you stick around and provide some more good insight...

Thanks for all the great suggestions! Many of them sound great.

Osaka Aquarium. But better yet, it's maybe 45 minutes to Kyoto, easily the most beautiful city in Japan. Catch the train to Kyoto, get a business hotel near the train station, you can easily fill up 3 days with all the sights there. Public transportation is great; you won't need a car.