Jeans and white trainers might have looked cool back in the days, when Chevy Chase was a popular actor. Not anymore. In fact, I think it's kind of embarrassing to wear trainers with jeans. For work-out, jogging or any sport activity, you wouldn't wear jeans. If anybody really wanted to wear sports shoes/trainers, they should either try to choose another colour or choose different styles. I had a few Adidas Spezial in various colours and they are great for driving and in the summer/spring/autumn. Nike's Wildedge GTX also has a few nice colour options. I have a pair in black/blue and they are fine.
Anyway, Jobs does wear suits occasionally but he doesn't look particularly good in them. Having said that, he still looks better than wearing those white trainers, ripped jeans and black hoody, where he looks like a hobo.
If I look back when he was more chubby, then without the beard, he would have looked like a certain PC guy in a certain advertising campaign.
By the way, there is a story circulating that Steve Jobs had to place a larger order with an upmarket high-street fashion chain to have his favourite turtlenecks manufactured again. Whether it's true or not, it's a marginally cool story.