Your roofing choices do not have to be limited to the old time standards of just shingles or metal. Not sure what you want, try searching pinterest for residential roofing pictures of shingle & metal roofs, we are sure it will help your imagination.
Does it affect your warranty?, No. Material and labor warranties should be the same no matter what choice of roofing you choose.
Will it cost more?, Yes. Think about this, when the average roof lasts 30 years on average, you can figure the additional cost of $2500.00, really isn’t that expensive. This of example using $2500.00, needs to be divided by 30 years to find out your true cost, which is less than 85.00 per year. When it comes to this type of residential roofing, the added value to your home far exceeds the investment you make.
*These figures are used for simplicity of explaining and can be lower or much higher in actual costs. Depending on your material choices, roof pitch and condition, as well as other factors like location.