My must-haves are: must allow cats, must have a backyard/trees, must have hardwood floors (carpet in one or two rooms is okay, though), and must be a reasonable commute to my work.
Deal-breakers are: electric stove (haaaate them), high-rise/complex (feels too much like I'm living in a hotel!), doesn't allow cats.
I'm starting to look for an apartment in my area and you'd be shocked how hard my must-haves are to find at a price below $1400 a month, but then I do live in the most expensive suburban area in the country. Sigh.