I agree that about 5+ years ago high credit limits could be detrimental but these days I find (personal experience) that having more credit available is beneficial as long as this credit is not used. I'm not convinced that my credit score would be as high if I had smaller limits.

As an example, Rogers (Canadian mobile phone company) slapped an R9 to my credit file about 5 years ago for 3 missed payments. Everything else (about 80K of credit was R1) and my credit score barely moved with this R9. I suspect that if I had very small credit limits this R9 would have been detrimental.

In the last year i applied for Amex Sky Blue, Amex Gold Business, Amex Gold Business, Amex Aeroplan Platinum, Amex Regular Platinum and I've been approved for all these cards. I'm not rich (far from it), I have a normal job, huge mortgage (I live in Vancouver) and I don't think high limits have ever been a problem.