I like to use manual settings. I love low light photography.

Tried and tested. This camera out performs D90, in so many ways, especially in low light photography. @ISO 3200 .. there's very minimal noise in NEX-5N. 

Compare them in Snapsort.com and dpreview.com.They are really helpful.DSLR is good but you can't take anywhere ,sometimes its odd you know to take it to some small party or relatives gathering..so I suggest Nex.But I don't strongly oppose the DSLR.DSLR the best machine.I haven't used NEX so I still stick to DSLR.. :) !

i guess dslr would give you better manual controls and lot of tricks that u can perform to enhance creativity - imp feature is the viewfinder which shows you exact picture while viewing on lcd screens may sometime capture slight diff things than displayed

both of these cams should give you good low light power - however check the things you need for those long shots like a remote trigger and stuff

I tried the Sony one out and was not impressed.

My Dad has the D90. I would use this Camera over the Sony one any day of the week.

But.......

K-30 just out performs those 2 and for a very good price.

Its much more expensive than the NEX, but the K-5 is a beautiful camera with excellent manual controls and superb high ISO performance. The NEX, meanwhile, is small, light, and has very good low-light as well, but it will limit your creativity.

The D90 is far inferior to the K-5 though... And considering they're at the same price-point, why not go with the better one? Umless you plan on upgrading to an FX body soon, there is no reason to go to a Nikon.