I am getting together another site, my branded site is zmiamirealestate.com now I am working on a name for my unbranded site. I was searching, miamihousefinder.com but it's taken, they have available variations such as miamihousefinders.com but I have read that many people searching will forget to add the s at the end, how about miamihousefinderonline.com? or zmiamihousefinder.com but they might forget the z. I am really confused on what name to choose. I will also have other domains within the site, I am working on those.
Your input is greatly appreciated.

which part of miami do you work in? how about westmiamihousefinder.com ? (or east, north, south, etc)

I am trying to concentrate in downtown miami, I will also buy downtowmmiamicondofinder.com to use for a landing page. But I came up w/Miamihouseinfo.com as the main domain, what do you think?

save some money maybe using .info? I've found the search results are the same.

What really matters the most is the CONTENT - they will find it in the search results and click on it. Not many will just type in domain names...they search for the search terms in google...the link appears, and they click on it.

Perky is right, most people are going to find you in the search engines, not typing it in right way [unless you have a domain that has a lot of type in's which is not likely].

how about:
www.homefinder4miamirealestate.com

Hi,
I am agreed with Perky. SERP of Google, shows the results indexed after looking the content on the site. Whatever name you will select, go with quality keywords for your site and optimize it well.

Hi,
As much I experienced, very few people use the url to search or go to a website, also many internet users uses phrases and search queries. Thus, not to worry about the domain name, go for relevant and competitive keywords and work hard on them.

Whatever domain name you register, keep in mind branding. If you have a domain name that is hard to spell or remember or easily misunderstood you will hurt your business.

I think your selections are fine and wouldn't worry about adding or not adding the 's' to the end. My main focus when buying a domain is making sure I use my keywords. The domain name isn't going to brand itself....you will brand the domain.

Best of luck!