Easiest direction to cycle in and out of downtown (fewest hills) is east. Not so, south or west. North is a gradual climb, flat for all intents, but Capitol complex and UT act as barriers, sort-of, to the north. And if you're not planning on using a bike a lot, then there are other considerations. The river blocks the south and all southbound traffic pretty effectively from 3 to 6 every day. It took me an hour recently, 5:30 to 6:30, trying several different southbound streets, to drive from 45th st. to Live Oak in south A. Could have biked it faster. Despite all the complaining, the Interstate moves cars faster than anything else from north to south and return.
Also better look into what amenities you want close by: not a lot of grocery stores south of the river, close in. Same east. Bars and restaurants are everywhere; I wouldn't make a decision on where to live in Austin based on that! Only exception: don't set foot in Williamson county, unless you're planning on setting up a baby factory and you think Rick Santorum would make a good neighbor; it's crazy once you get out into the burbs. You've been warned. Edited by Spats - 2/8/12 at 3:59pm