In the UK you can get DVD players which have either both PAL and NTSC output or which convert NTSC into PAL or "pseudo PAL" (50Hz) output. The first allows you to play back NTSC on a TV which is both PAL and NTSC capable, the second on any PAL TV.
The problem arises when you get to the USA. As usual, they find it difficult to believe any other system exists.
In the USA you can only get DVD players with NTSC output. Fine for playing back your NTSC tapes, but not for PAL. There is no DVD available which has a "pseudo NTSC" mode for playing back PAL tapes.
Since you can't translate the PAL into NTSC in the DVD you have two options. Buy an external decoder or PAL/NTSC TV.
You can get real-time decoders, but they're expensive, BAL has taken a slightly cheaper option to do it non-real time.
As with DVDs, you can't get dual PAL/NTSC TVs in the USA. Taking a European one runs into other problems.
The answer is a Plasma screen as they have to convert all systems for display using an internal scaler. You can buy a good 42" for under $3000
(see here). Add a multii-region DVD with both true NTSC and PAL output and you're home and dry. (or buy one one of each, they're cheap enough these days,and you don't have to worry about region codes and compatibility)