As somebody who DID work as a systems administrator for a publicly traded, Canadian based company that supplies software to the online gambling industry I can say that unless you're an executive it will have no bearing on your future employment any more than working for an 'evil' defence contractor or such will. Sure, you'd have a hard time getting a job at amnesty international after working for BEA, but the experience you'll get will open more doors elsewhere. The company had far more trouble hiring people who were willing to work for the company, in fact. Though in Canada 'online gambling' had a much more negative connotation than it does in England, where betting shops are everywhere.
The experience I got was very worthwhile. I got to travel to interesting locations to setup the servers. Places like Curacao in the Caribbean, Malta, Ireland, the netherlands (we did work for the government casinos there, in fact), etc. I started out in a very jr position, but moved up extremely quickly because I was capable and they had a hard time finding good people who were willing to work for them. This gave me Sr-level quality within 2 years. I've since moved on, but I would do it again in a second. It's not been a black mark on me at all and people are usually curious about it. Because of complex legal and national regulations, the accountants also were in a similar position. They had a lot of trouble getting quality accountants, so they had to get more Jr. ones who moved up fast.
The executives had far more trouble after leaving, though they also ran the company rather poorly. In fact I'd say that the worst part was having to work with/for some people that I would consider less than high caliber. Because of this, I became the go-to guy to fix poor decisions made from incompetence at the CTO and director level.