A connect snippet that utilizes a dialog and mirc's mirc.ini as a database for your default server, nick, alternative nick and password. You also have the option to auto-join channels and disable the auto-join feature when it is not wanted.

To change your default server: /paramsc.config server (new server)

dialog auto.con {
  title auto-connect options
  size -1 -1 99 97
  option dbu
  combo 1, 7 14 81 11, drop
  text "Server:", 2, 12 3 33 8
  list 3, 7 39 78 41, size
  button "+", 5, 24 81 20 12
  button "-", 6, 44 81 20 12
  menu "Nickname configuration", 7
  item "Default", 8, 7
  item "Alternative", 9, 7
  item "Password", 10, 7
}

on *:dialog:*:*:*:{
  var %x = 1
  if ($dname = auto.con) { 
    if ($devent = init) { 
      set %sclick 1
      did -a $dname 1 $readini(mirc.ini,Userprofiles,server) 
      did -b $dname 3,5,6
    }
    if ($devent = sclick) { 
      if ($did = 1) && (%sclick = 1) { 
        if ($readini(mirc.ini,Userprofiles,server)) {
          did -e $dname 3,5,6
          inc %sclick 1
          while (%x <= $lines(auto-joins.txt)) { 
            did -a $dname 3 $read(auto-joins.txt,%x) | inc %x
          }
        }
      }
      if ($did = 5) { 
        var %i = $$?="Enter channel to add."
        paramsc.config add chan %i
        did -a $dname 3 %i
      }
      if ($did = 6) { 
        if ($did($dname,3).sel) { 
          did -d $dname 3 $did($dname,3).sel
          paramsc.config rem chan $did($dname,3).sel
        }
      }
    }
    if ($devent = menu) { 
      if ($did = 8) { 
        writeini -n mirc.ini mirc nick $$?="Enter your main/default nickname."
      }
      if ($did = 9) { 
        writeini -n mirc.ini mirc anick $$?="Enter your alternative nickname"
      }
      if ($did = 10) { 
        writeini -n mirc.ini Userprofiles password $$?*="Enter password for your nick" 
      }
    }
    if ($devent = close) { 
      unset %sclick
    }
  }
}

raw 433:*Nickname is already in use*:{ 
  if ($1 !iswm $readini(mirc.ini,mirc,anick)) { 
    nick $readini(mirc.ini,mirc,anick) 
  }
}

on ^*:notice:*:*:{ 
  if ($nick = Nickserv) && (identify isin $1-) { 
    msg $nickserv $readini(mirc.ini,Userprofiles,password)
  }
}

on *:Connect:{ 
  var %x = 1
  while (%x <= $lines(auto-joins.txt)) {
    join $read(auto-joins.txt,%x) | inc %x 
  }
  if ($gettok($readini(mirc.ini,Userprofiles,auto-join),1,32) iswm active) {
    msg Nickserv identify $gettok($readini(mirc.ini,Userprofiles,password),1,32)
  }
}

alias paramsc.config {
  if ($1 = add) { 
    if ($2 = chan) { 
      if ( $read(auto-join.txt,$3) ) { echo $color(info) -a Invalid syntax: Channel $3 already exists. | halt }
      else { write auto-joins.txt $3 }
    }
    if ($2 = server) { 
      if ( $readini(mirc.ini,Userprofiles,server,$3) ) { echo $color(info) -a Invalid syntax: Server is already set as default. | halt }
      else { writeini mirc.ini Userprofiles server $3 }
    }
  }
  if ($1 = rem) { 
    if ($2 = chan) { 
      write -dl auto-joins.txt $gettok($read(auto-joins.txt, $3),1-,32) 
    }
    if ($2 = server) { 
      remini mirc.ini Userprofiles server 
    }
  }
}