buying my first road bike

Hi

I'm going to by my first road bike. It's going to be second had bike. So I'm looking to find best bike for least money.

I have few questions:
- how much important is the number of driven kilometers on used bike?
- which "equipment" do I need (I don't need the best, neither i don't want the worst). I was thinking of Shimano Ultegra or. Compagnolo Centaur or. Veloce
- which size of frame do I need if I'm 186 cm tall? Are all frames from alll manufactures the same size?

I will drive about 3000km a year and I wanna have this bike for at least for 5 years.
This is why I need to know how important is number of driven kilometers on used bike.

Thanks in advance and sorry for my bad english

Hope I can give you some helpful answers.

- how much important is the number of driven kilometers on used bike?
Not important at all if the bike has been well maintained and not crashed. Tires, brake pads, cables, chains, and freewheel cogs do wear out, but they are generally replaced as needed.

- which "equipment" do I need (I don't need the best, neither i don't want the worst). I was thinking of Shimano Ultegra or. Compagnolo Centaur or. Veloce
Ultegra, Centaur, and Veloce are all fine. So are Shimano 105 and SRAM Rival.

- which size of frame do I need if I'm 186 cm tall? Are all frames from all manufactures the same size?
Different manufacturers proportion their frames differently. Most measure center of bottom bracket to top of seat lug now, so at least that's standard. Compact frames sizing (XS-S-M-L-XL) is definitely not standardized. Best to take a tape measure.

At 186 cm, try a 60 or 62 cm bike, for starters.

Hi

I was looking at Fuji ROUBAIX PRO bike. Some says Fuji bikes are not that good.
What do you think? Is there any professional team that uses Fuji bikes?

Fuji makes very good bikes. They dont have a European team on their bikes so the brand may not have reputation for being a serious bike. USA cycling team Toyota United rides Fuji's. A local racing team in my area rides Fuji's. But if your buying a used bike make sure you check it out no matter what the brand is. You can probably have a local bike shop check it for you. They might charge a fee but it's worth it if they find a small crack or other damage that will cause the bike to be useless.