Once again we are in that area of - "What do YOU want in your product?"
Price, strength, weight, color?
Titanium spokes are crazy expensive and are more durable than steel. They usually weigh less than steel spokes, but because Ti can stretch somewhat, then you are likely to need to regularly true your wheels to compensate for this.
Double butted, stainless steel spokes, in my opinion, are the best value. Just a few bucks more than straight gauge spokes and you save some weight while maintaining strength at the most critical point of contact - the spoke and the hub and the spoke and the rim.
Straight gauge, stainless steel spokes are an excellent value and cost less than the others listed. They work and are high quality. These 14 gauge spokes are probably the most common spoke that are run by riders. 12 gauge is almost always overkill and adds a lot of weight to your ride.
I am not aware of any brand names actually being better than their more generic counterparts, but you can almost always count on the Marwi type spoke to be of the highest quality out there. So, spending money on that brand name may give you more peace of mind than anything else. Since spokes (except Ti) aren't really that expensive, going with a brand name won't break the bank.