The problem with recomending particular bulbs is that it all depends on personal preference and what you want to keep, where you are planning on just keeping fish it is all aesthetics. What I have done in the past is check out different tanks, find pics like some that are on this board and PM the person with the most appealing look and ask them what combo they use.
Typically if you like a whiter look go for somehting around 10,000-15,000K if you like a bluer light go higher like 18,000K.
As far as the different bulbs at same temp, they tweak the bulb to have similar human eye visual appearance but have different spectrum out put i.e.; normall a 18,000K bulb is mostly blue spectrum but some of the bulbs with 18,000K will have spikes in red (good for plants).
Typically if you like a whiter look go for somehting around 10,000-15,000K if you like a bluer light go higher like 18,000K.
As far as the different bulbs at same temp, they tweak the bulb to have similar human eye visual appearance but have different spectrum out put i.e.; normall a 18,000K bulb is mostly blue spectrum but some of the bulbs with 18,000K will have spikes in red (good for plants).
flamed