Welcome welcome to the forum
Read up on the lens reviews and lens club threads on the forum is your best bet.
I do have the DA 40mm F2.8 XS and the "Plastic Fantastic" DA 35mm F2.4 which are two great lenses.
My 40mm is still so new so I can't give you my honest recommendation which one is the best yet...
Love both of them
You might want to take a look at the FA 31mm, FA 43mm, DA 40mm Ltd and the DA 35 Ltd Macro there is of course more out there but it all comes down to you and your wallet
Cheers
Yos