I like THE CODE by Andy Nyman. The markings not only tell you that card but also the next one and the location of the card in the deck.
I recently bought the DMC marked deck, and this has become my favorite. My eyes are not that great but the very clever markings are very easy for me to read even at 4 or so feet, yet very difficult to spot if you don't know the system. A disadvantage might be that they are not a Bicycle deck. But still, if you are only buying 1 deck I would go with this. If you can afford it I would recommend buying this and The Code.
My recommendations in order of preference.
1) DMC Deck.
2)The Code by Andy Nyman. The most versatile.
(If you have excellent eyesight this should be your first choice.)
3)The Ultimate Marked Deck. (Very well hidden markings but not for less than perfect eyesight)
4) GT Speedreader. Also very nice.