There's a difference between becoming a better developer and showing you're a better developer to potential employers or to your current employer (ie. raises and such). I'm wondering what the most cost effective ways of doing that are. By cost effective, I don't just mean how much money said developer going to have to put out. Most commonly these are money and time. The latter is often more significant.
For instance: Having your own blog can really develop you as a programmer, but it may not be seen as a big deal to your current or future developers, and is potentially a lot of work, whereas some certs can go a long way with some employers and is much less work than building up a lot of quality content in a blog or developing a personal/OS project - even if the latter may be more fun.
Assuming you're in the .NET space, what are the more cost effective ways that you can increase your marketability to your current or future employers? In an ideal world, we/I would do them all, but for the purpose of prioritizing, one should/could tackle the higher marketability/cost ones first before moving on to the others.