I deal mostly with local search engines and have top rankings in many places around the world.
there is a big difference in SE results localization. it might sound weird but , as younger the search engine as better his localization is.
you can see for your self that MSN dedicate his results, marketing and efforts to local distributions. in the same way see how MSN local organization works. msn.se / msn.co.il / msn.com.au .... each one of them is localized by results , info , rules , design and management.
yahoo is second best and optimizing local data mostly for the US.
Google is just now getting in to it and building the Google earth DB is a step towards global localizations. as Google always does , it is too big and way to good to be used by the simple user.
now to answer your question, local parameters will reflect your site in the local SE.
1)IP (site , dns , domain registrar)
2)domain prefix. (co.uk ...)
4) outer reciprocal Links ?
5) inner reciprocal links?
6) and most important ... how many people like you are fighting over the top rankings.