Those are strains bro,basically they take one strain cross it with another and it becomes something different and generally takes on the characteristics of whatever is crossed together. All hydro means is hydroponics which is a way of growing not a type of plant of anykind. Each strain has different characteristics. Some are made to give you a nice head high and smooth smoke,others are made to kick your ass,sometimes it just for how they can grow too possibilities can be theoretically endless. You mentioned White Widow which happens to be my favorite.If you've never tried some I highly recommend it but dont plan on going anywhere for a while if its grown right.In your area of NYC is where diesel originated if I remember correctly.Diesel of anykind is generally badass so try it out too. in fact any of the strains you listed are very good,Kush type strains at least in my opinion have a very nice and relaxing head high,can never go wrong with any types you listed thou. If you do a google search for attitude seedbank and go to the site and just checkout some of the stuff it has descriptions and characteristics of each type,kinda neat stuff to read.