After IIS reset, first hit taking a long time because AppPool is starting and other .NET components, DB connections are initializing.
What would be the best way to
For IIS 7.5 you can using the Application Warmup Module -
http://www.iis.net/download/applicationwarmup
Some tips on warm up scripts:
http://www.andrewconnell.com/blog/archive/2006/08/21/3882.aspx
More info on the IIS site:
http://blogs.iis.net/steveschofield/archive/2009/05/30/application-pool-warm-up.aspx
Check out the latest news under "Auto-Start Web Applications" section here:
http://www.asp.net/LEARN/whitepapers/aspnet4/default.aspx
You will find the script posted on http://blogs.msdn.com/joelo/archive/2006/08/13/697044.aspx. Though it is meant for sharepoint but it will work just as fine with any IIS web project. You may need to adjust the file to make it hit the different applications pages you want.