We hardly use or bother with Region 4 (Argentina) and most of the stuff aound is either Region Free (R0) or R1.
Comercial DVD players are mostly R1 and R4. Others can be unlocked by punching codes.
If you plan to buy local, Philips does the most compatible players. Fugly design but extremely multi-region friendly and forgiving players. Will play last week's leftover pizza slices for you. Samsung is also OK. Sony is bitchy and picky as hell.
Computer Media/Video players can be told to disregard Region.
If your DVD player tells you that you must change regions to watch this or that DVD it's time to change sofwares and look for the ones that do not check region.
Rule of thumb, most current TVs are dual standard, NTSC and PAL N. Cable signal is NTSC, DVDs are NTSC.
UK uses PAL and US uses NTSC. Not a region coding issue.