Some bright southern galaxies are LMC, SMC, NGC55, NGC253, M77
NGC1291, NGC1316, NGC3115, NGC3521, M104 and M83.
The brightest objects in the sky have negative magnitudes:
Sun = -26.7, Full Moon = -12.5, Venus = -4.4, etc
The Sun and Moon are bright because they are close.
If the Sun was 10 parsecs away it would be magnitude +4.8.
M88 at the same distance would be magnitude -23.1.
See:
http://www.historyoftheuniverse.com/magnitude.html