Standard tuning for most ukes (soprano, concert & tenor) is gCEA reentrant; i.e. the G string is tuned to a higher pitch than the C string. The reentrant tuning is part of what gives the uke its character and it is essentially a strummed instrument. You can pick with a uke and it can work very well but you can't do bass runs as there are no bass strings, so picking basically involves playing arpeggios in the treble register.

The baritone uke is tuned DGBE, commonly with a low D string but even in this case quite a few folk use reentrant tuning with a high D string.

Also quite a few uke players like a low G string in otherwise standard tuning. This is especially true of tenor uke players. Quite a lot of discussion on the ukulele forum I belong to revolves around the high G/low G issue.

You might notice that if you capo a guitar at the fifth fret, the top four strings match standard uke tuning with a low G string.