I already have 2 boys and I do plan on having a least 1 probably 2 more kids...
that said, i am an only child and i NEVER felt like i missed out - i didnt know any differently. being an only child didnt factor in (intentionally) in my decision to have a bigger family...
I wasnt lonely (and it was just me and mum from when my dad passed away when i was 8) - i had heaps of cousins, went to FDC with a family with 8 kids all of who were like siblings to me (they still are). I also was always allowed to have friends stay over and mum always invited 1 or 2 of my friends on holidays with us etc. so she made sure i was surrounded by kids...
i dont think 'guilt;\' is a good reason to have a child - if you chooose to you will love them of course, but you cant predict how they will relate to each other (through life...) and there are other ways to give you child companionship etc.