Anyone been to Scotland and/or Ireland?

I have decided that in the spring of 2012 I want to vacation for 10 days in Scotland/Ireland. I have always wanted to see it as it has significant history and is truly a beautiful place. Has anyone here been to these places either for vacation or lived there? What cities are best to see historically? Is it best to go with a group tour or should I just go solo and find my way about? Are the people friendly there? How much US currency should I bring to spend on gifts? What is the weather/temperature like that time of year? Any and all answers would be a great help. Give Thanks for your time.