The style of roof gutters that you choose can vary widely, as can the material of the gutters. Copper, steel, and aluminum all have their use in a gutter system, so there are several very good materials to choose from. Aluminum is probably the most common, as it's in wide use, it's easy to work with, and it's relatively cheap. In addition, aluminum can come an many different colors, so it is very easy to find a style that fits your house. Steel gutters are a more durable option than aluminum, as steel is thicker and tougher. It will need stronger supports on the house, of course, and it is prone to rusting. Steel gutters can be treated to not rust, but the wear and tear of years on a house may lead to some rusting over time.
Roof gutters can also be made of copper in order to have a very distinct look. Burnished copper is treated to hold its copper color, as opposed to ordinary copper which starts out a dull copper color and slowly fades to a greenish tint that can impart the look of a 'stately old mansion'. If this style suits your old house, go for it.
At the two extremes of roof gutters are vinyl and cast iron. Cast iron would be a good choice for the stately old mansion look for an old house as well, since it goes very well with stone work. Like steel, cast iron can be treated to prevent rusting, but because it is a metal that does rust, you may need to reapply a treatment after some years. Just keep an eye on it, which of course you'll do, since you'll need to keep the roof gutters clear of debris. Vinyl roof gutters are quite the opposite, as they cannot rust and are very light weight. Vinyl can be extruded thick enough to hold up fairly well on a roof, and it's low cost makes it a popular option. Like aluminum gutters, vinyl roof gutters come in a wide range of colors, so a color can be found to match any style that your house has.
Don't forget accessories when choosing roof gutters. Most important is some kind of gutter guards to keep debris out of the gutters. Keeping gutters clean is a necessary task to prevent build up of water and especially ice in northern climates. If a passive gutter system can be put in place to reduce the amount of debris that has to be removed by hand, by all means do it. There's enough maintenance to be done on a house without pulling out a ladder, so roof gutters that reduce cleaning are the ones to choose.