Let's be clear here.

Any query that takes 30 hours to finish isn't poorly written. It's just broken. Yes, you fix that stuff.

My normal metric for a query if it's correct, it will typically run in < 100ms if it's simple, or < 1sec if it's a report, or < 1 min if it's along the lines of a year end report done on transactional data.

The thing is, if you do those year end reports everyday, then 1 min is for me, broken. It should be redone to be < 100ms.

In no way should what I said be construed to say that a system with hundreds of gigs of randomly generated/stored transactional data, and crappy RBAR code can suddenly become usable if you throw more iron at it.

Not sure if that helps, or just adds more sparks on this subject.