It depends on your budget. There are a few threads that deal with your situation ("newbie needs advice on hardware"), but here's the short version:
(1) $$$$$. You will most likely want to explore the AWESOME library of CD-ROM games at some point. So, you should definitely get a DUO-R or DUO-RX (Japanese models) since they have (thus far) the best reliability. You can play Japanese HuCARDS on this system. If you modify the system (or pay someone here to do it), then you can get a region switch installed that will enable you to play US HuCARDS. This would be nice for a handful of HuCARD games where the English-language version is more pleasurable to an English-speaker. If you don't want to get a region switch, you could always pick up a cheap TG-16.
(2) $$. Get a TG-16 and/or PCE CoreGrafx I/II. Some of the US HuCARDS have ridiculous prices, so you may want to get a PCE for the cheaper Japanese version. CAVEAT: Some games, like Neutopia I & II, Dungeon Explorer, etc. are more fun in English if you are an English-speaker. PROBLEM: You will explore the HuCard library until you finally realize that you MUST PLAY all the CD games! At this point, you could sell your base TG-16/PCE and invest in a DUO-R/RX.
NOTE: Option 2 is perfectly fine for folks on a budget. There are many wonderful, cheap HuCard games to occupy you. But, make no mistake, you WILL EVENTUALLY lust for the CD games.