Synth / module recommendations ("realistic" sounds)

I have a friend (oh boy, one of these threads) who is looking to upgrade from an ancient Yamaha synth. He is a very talented keyboard player and is more interested in having good sounds than building his own sounds. He isn't interested in an analog synth at all and likes to have a palette of realistic type sounds, sorta like you would find in a typical Casio or arranger. He even made the comment that he liked the sound of a certain Casio vs. some other Yamaha synth he was looking at.

So my question is: what would you buy on a limited budget if you wanted good "real world" instrument sounds. I was thinking maybe a MIDI sound module might be good (like the Kurzweil ME-1, or Roland JV series?) so he would have expansion options but there are so many to choose from. I was thinking one of the older Roland Fantom series might give him additional options like sampling. A legitimate answer is indeed also "there is a really good Casio XYZ".

Thanks for your assistance.

I am totally out of my element here but i was checking out the GW-7 on Roland's site and i think it sounds really good. It seems to lack that annoying digital Rompler sound.

Just wanted to add it to the list.

I'm going to say used Kurzweil for acoustic sounds. K2000s are pretty cheap now.