Microsoft SQL query help- Selecting Max date

Greeings Experts,

I am having a problem completing a Microsoft SQL query.  I have posted another question but still can not get this working.  Here is problem.  I have a table that looks like this

Table1
Studyinv_ID        Visitdate          Visit_Type_ID          VisitName
1698                  12/7/2006            26                        Closeout
1699                 10/20/2005            23                       PSSV/Initiation
1699                 10/20/2005            25                       Monitoring
1700                 10/31/2005           25                        Monitoring

What I am trying to do is group by Studyinv_ID and show the max date and its corresponding VisitName.  The problem I keep having is when there are 2 identical dates (ie rows 2,3).   No matter what I try, I get 2 results in the output.  For example, I want the output to look like this...

Studyinv_ID        Visitdate          Visit_Type_ID          VisitName
1698                  12/7/2006            26                        Closeout
1699                 10/20/2005            25                       Monitoring
1700                 10/31/2005           25                        Monitoring

The key (i think) is to somehow incorporate the Visit_type_ID as a max but I cannot figure it out.  I have attached the table data if you want to see it for reference.  Thanks.
table.xls