This might help. It groups the books by their more prominent characters and storylines. Might make it a bit easier to digest and pick which seem the most interesting entry point to you.
ETA: Though now that I look at it, it has Carpe Jugulum in the wrong order and seems to have forgotten about 'A Hat Full of Sky'.
Others have their favourites I'm sure, but I think it's a given that the City Watch books are probably the easiest for most to get into since they're the most grounded.* They're also handy as a primer as they almost all take place in the city of Ankh-Morpork which features or is mentioned in most of the other books to a greater and lesser degree. As Terry put it:
"There's a saying that all roads lead to Ankh-Morpork. And it's wrong. All roads lead away from Ankh-Morpork, but sometimes people just walk along them the wrong way."
Don't worry too much about continuity as each book is generally written so that it can serve as *someone's* first Discworld book. That accessibility is part of why the series is so long lived and successful, it never suffered from continuity bloat.
That's not to say that there isn't any continuity (quite the contrary) is just that it's only there for as much as it needs to be.
* Relatively speaking ,in a world that involves Dwarves, Trolls, Zomb--uh, the "differently alive" and Nobby Nobbs...and quite literally speaking once Sgt Detritus shows up.
Oh and in case anyone missed the news,
The Jim Henson Company are doing an adaptation of 'The Wee Free Men'. Crivens!