I would say that it would be dependent on what it is you are planning on doing.
A small pen style low wattage will work for small thin items.
A little higher wattage pencil style irons 35 watts and up for a little heavier items
There are as many soldering guns in assorted sizes I have a number of them and had others over the years. None seemed to work as advertised.
The small compressed gas torches or irons work for things that are close together or the heat can travel.
The large irons, electric 100 watts and up are good for larger items.
There are the old standby irons that require an outside heat source good for long or large sheet good seams.
Then there is the new generation of electronic soldering iron stations with adjustable temps. I have a Chinese import from the hated Horrible Fright company. Haven't used it a lot but it works as advertised.
The sal blocks are for the sheet goods/external heat irons
The round point bits are the replacement bits for the electric irons.
American Beauty is a long and old brand in the US that are great as I have some 50 year old ones and they are still working.
Then if you are doing a lot of close together bits and pieces there is the resistance soldering rigs.
Here is a good resource for soldering of all kinds with video's
http://www.americanbeautytools.com/site/