Work vs. Family relations -- what's your priority and balance?

I ask because I used to devote a lot of time and money to workplace relations, only to find that even profound relations with the most wonderful people at work turn hollow within a year or two after you've both moved to different jobs (whch is often, in this day and age). Since last year, I've made family a top priority because they're going to be with me forever. Still, it's hard to juggle the two because I prefer not to get too involved in a half-ed way with people when I feel it'll be a fleeting relationship, even if you do spend 10 hours a day with them. Does anyone else feel guilt or doubt about putting family ahead of co-workers? How do you come across the right balance?