moving to Europe,need help with converting 110/220

5000W converter must be an expencive device for shure but maynot be enough depending on the power/ch of your AVR.
check with manufacturer(s) if you can eliminate few of your components by simply switching to 220V operation. most receivers do have that to begin with.
as to dvd-player don't even bother -- it'll shurely work.

Things like amps (and your sub) should run fine off a step-down transformer...the 50 Hz difference is only a concern for things such as turntables that use the power line frequency as a speed reference. I ran my Velodyne HGS-12 just fine off a transformer.

I moved from the States to Paris 3 years ago, and was faced with the same problem (110V gear running on 220V). Fortunately some of my equipment (Quad and Revox) is multi-voltage, no problem there. The rest is 110V equipment, Including two 200W/channel power amps. I simply purchased a 2kW 220V/110V line stabilizer transformer (~$200). You can purchase the equipment from www.eastwestintl.com or www.220voltappliances.com. The other thing to remember is, HiFi equipment in Europe, especially high end gear, is a lot more expensive then in the USA. Bottom line, bring your equipment with you and use a voltage stabilizer step down transformer to run it.

However, one thing to consider, and I learned the hard way. Certain US high end manufacturers (Krell for certain in the last ~10 years, and, I believe Martin Logan and others) put a frequency sensing chip on the power input circuit. This senses if you are running 60Hz (US) or 50 Hz (Europe) mains voltage (irrespective if it is transformed down from 240/220V to 110V and will not work if the power source is 50Hz. Krell in France charged me $180 to have my Krell HTS converted when I experienced this problem. Check before you leave!