Ok, you asked for it, here is the quickest way to count the number of lines in a text file.
Code:
Option Explicit

Function lineCount(myInFile As String) As Long
    Dim lFileSize As Long, lChunk As Long
    Dim bFile() As Byte
    Dim lSize As Long
    Dim strText As String
    
    'the size of the chunk to read in.  You can experiment
    'with this to see what works fastest.
    lSize = CLng(1024) * 10
    
    'size the array to the chunk size
    ReDim bFile(lSize - 1) As Byte
    
    Open myInFile For Binary As #1
    'get the file size
    lFileSize = LOF(1)
    
    'set the chunk number to 1
    lChunk = 1
    Do While (lSize * lChunk) < lFileSize
      'get the data from the in file
      Get #1, , bFile
      strText = StrConv(bFile, vbUnicode)
      
      'get the line count for this chunk
      lineCount = lineCount + searchText(strText)
      'increment the chunk count
      lChunk = lChunk + 1
    Loop
    
    'redim the array to the remaining size
    ReDim bFile((lFileSize - (lSize * (lChunk - 1))) - 1) As Byte
    'get the remaining data
    Get #1, , bFile
    strText = StrConv(bFile, vbUnicode)
    'get line count for this chunk
    lineCount = lineCount + searchText(strText)
    
    'close the file
    Close #1
    
    lineCount = lineCount + 1
               
End Function


Private Function searchText(strText As String) As Long
    Static blPossible As Boolean
    Dim lp1 As Long
    
    'if we have a possible line count
    If blPossible = True Then
      'if the fist charcter is chr(10) then we have a new line
      If Left$(strText, 1) = Chr(10) Then
        searchText = searchText + 1
      End If
    End If
    
    blPossible = False
    
    'loop through counting vbCrLf's
    lp1 = 1
    Do
      lp1 = InStr(lp1, strText, vbCrLf)
      If lp1 <> 0 Then
        searchText = searchText + 1
        lp1 = lp1 + 2
      End If
    Loop Until lp1 = 0
    
    'if the last character is a chr(13) then we may have a
    'new line, so we mark it as possible
    If Right$(strText, 1) = Chr(13) Then
      blPossible = True
    End If
    
End Function