What is the evidence that someone is filled with the Holy Spirit? There seems to be a distinction between being filled with the Holy Spirit and being indwelt with the Holy Spirit.  The book of Acts mentions the filling of the Holy Spirit several times.

What specifically is the evidence that someone is filled with the Holy Spirit?  Is there always evidence that can be observed by others or can the filling be indistinguishable sometimes?
Various traditions have different answers on this.  There's no consensus. (That may be your answer.  The rest may be irrelevant.)



Greg Bala has already addressed the Catholic view.  Here are some Protestant ones, ranging from extreme Pentecostal to conservative Christian.  None of these are universal.  Some groups believe some of them, others think that some of the beliefs are insane, pure guff, or just wrong.  I'm not saying which is which, just listing them out.


Ability to pick up deadly serpents, not get bitten, and be immune to their poison if they do bit you
Being overtaken with Holy Laughter
Prophecy
Growling, dancing, shaking, barking like dogs, and even some even being stuck in positions of paralysis.
Speaking in tongues


On the less Charismatic end of the spectrum...


Possessing the fruits of the Spirit - a combination of Matthew 7:16 and Galatians 5:16-25.  Many non-Charismatic protestants see these fruits as evidences that we are filled with the Spirit.



  Matthew 7:16 (KJV) Ye shall know them by their fruits. Do men gather grapes of thorns, or figs of thistles? 
  
  Galatians 5:16-25 (KJV) 16This I say then, Walk in the Spirit, and ye shall not fulfil the lust of the flesh. 17For the flesh lusteth
  against the Spirit, and the Spirit against the flesh: and these are
  contrary the one to the other: so that ye cannot do the things that ye
  would. 18But if ye be led of the Spirit, ye are not under the law.
  19Now the works of the flesh are manifest, which are these; Adultery,
  fornication, uncleanness, lasciviousness, 20Idolatry, witchcraft,
  hatred, variance, emulations, wrath, strife, seditions, heresies,
  21Envyings, murders, drunkenness, revellings, and such like: of the
  which I tell you before, as I have also told you in time past, that
  they which do such things shall not inherit the kingdom of God. 22But
  the fruit of the Spirit is love, joy, peace, longsuffering,
  gentleness, goodness, faith, 23Meekness, temperance: against such
  there is no law. 24And they that are Christ's have crucified the flesh
  with the affections and lusts.
  
  25If we live in the Spirit, let us also walk in the Spirit. 26Let us
  not be desirous of vain glory, provoking one another, envying one
  another.