We're considering to implement some good/better/best recommendations in our existing Mid-Large SP Farm for "Single point of Failure in SharePoint 2010". Can someone point out to the areas which can be considered?
This is probably far too complex of a topic to get a good, direct answer to your question from a Q/A forum. It depends on a very large number of factors, such as cost, geographic distribution, your SLA, etc. Here are some resources to get you started, though:
SharePoint 2010 Enterprise Architect's Guidebook [Amazon] - This book has a great overview and good degree of detail over nearly every topic that you will need to know about to architect a scalable SharePoint farm.
Planning and architecture for SharePoint Foundation 2010 [TechNet] - Microsoft's guidance architecting a SharePoint 2010 farm.
Plan for availability (SharePoint Server 2010) [TechNet]
Someone on your team should also have a good understanding of SQL Server best practices for deployment and clustering.
SQL Server Best Practices [TechNet]
Failover Clustering Overview [TechNet]
The best direct advice that I can give you right now, is study as much as you can and then come back and ask more specific questions regarding your company's specific needs when you have them. Right now your question is a little too broad to get an answer other than some suggestions for reading.