Hi STM,
Yes those born in the year of the Monkey are not advisable to get married in Tiger yr. This is the first rule of wedding date selection. Coz in Bazi, Tiger and Monkey clashes. And any clashes to the year has the greatest impact.
Bazi wedding date selection can only help if you really want to get married in tiger year, but cannot overcome the fact that it clashes.
Even if you go by very general Tong Shu date selection, when you open up the Tong Shu for 2010, you will realise every single day throughout the yr, the Monkey sign is deemed as inauspicious.
Therefore, as you can see, no matter which method you use, it is still not advisable.
The negative impact is that it will bring bad luck to your marriage, and also things may not be so smooth on your wedding day. How bad luck it is will of course depends on your Bazi, whereby the severity and level is different for everyone.
Yes you are right. If one of you are born in Monkey yr and the other Rooster yr, then the next best yr to get married is the Dragon year, which is year 2012.
If this is the case, the next best alternative will be to ROM in 2009 and AD in either 2010 or 2011 (IF you really really really have to do it in 2010 or 2011!!!). At least the ROM, which is the important day where both of you are husband and wife legally, falls on a good yr and day. This is just an alternative. I still prefer to do everything in 2012 (if possible).
Hope this helps.