I don't use spotlight all that much but when I do, it always shows me exactly what I'm looking for within a few keystrokes (I primarily use it to launch applications that aren't in my dock, but also to find documents etc.)
So I am curious about what problems Mark has with Spotlight, and also what advantages the Alfred app might bring. I remember using Quickilver as others have suggested a few years ago to replace or supplement Spotlight, but I can't remember why because Spotlight seems fine (it didn't used to be as good, granted, which may have been why I looked for something to supplement it). It looks like Alfred has a bunch of neat features, but if I'm honest, none of them look like things I'd ever really use.
On a different topic, the Airmail app looks like exactly what I've been looking for. I just recently switched to Apple's Mail app for the first time - when I first switched to a Mac I carried over using Thunderbird from Linux, but it was slow and buggy, so I switched to the great Sparrow app (meant primarily for gmail), which Google bought out and then killed and which despite receiving no updates eventually stopped working altogether for some reason, so I switched to Inky, which is OK but needs a lot of work IMO (unnecessarily quirky, it's in beta though, understandable) and uses a lot of system resources.
So I switched to Mail for simplicity a week or two ago and it's perfectly fine, but not as nice as the things built for or based on gmail. Airmail looks like it's very similar to the Sparrow design philosophy I liked.
Some other stuff in my menu bar:
Chrome notifications - this doesn't seem to work for me either
adium, dropbox, google drive
fl.lux - makes the screen colors warmer at night. Happens gradually at sunset (based on your location) and your eyes adjust and you really don't notice, but it's noticeably less straining. I've been using it for years and I notice immediately using other peoples' computers at night that they're bright and hurty. Disables automatically when you switch to programs of your choosing (like photoshop/lightroom for me).
Caffeine - clicking the icon fills the mug with coffee, and then the computer won't turn the display off or go to sleep etc. for an hour (or a default of your choosing, or select a different amount of time from the right-click menu). Very useful.
MiddleClick - this is a background process that turns a three-finger touchpad tap into a middle click, for opening new tabs etc. There are more advanced gesture apps that do the same and more and I've tried them, but they're less reliable (i.e. they don't actually work half the time you try to do a gesture, which is annoying and frustrating) and this is the only thing I really want on top of the built-in stuff anyway. I open about a million tabs a day using a three-finger tap instead of having to hold down a keyboard key.
I have a network status, CPU and RAM monitors (with a drop-down menu showing what's using the most resources - I check these constantly when things are running slow to see what the culprit is), and a better battery monitor, these come from iStat Menus. Apparently I'm on version 3, which IIRC was free, and version 4 is now $16. I do use it all the time but not sure I'd bother paying for it on a new computer... there are a million other features you get for that $16 that I don't actually use myself.