There isn't much to be said here, just HUDs and crosshairs.
HUDs.TF is the way to go. Or just ask around which HUDs other people use and like, that works too!
MrSlin has made a vid showing off some of the most popular HUDs.
If you can't decide between so many HUDs give RaysHUD by Rays a try!
There's also a big thread on the TFTV Forums with a lot of custom HUDs, some of them aren't on HUDs.TF yet.
I don't feel the need for custom crosshairs, like the Konr Wings or others, and so I can't give any info (for now) on this. I used TF2 Mate to configure my crosshairs (simple ones, that come with the game, like the + , X , O , etc), for each class and weapon slot. You can also set to turn viewmodels on or off for each slot.
NOTE: The crosshairs for the spy on TF2 Mate are bugged. It will always be a white dot, independent of which crosshair you choose.
It comes that time when you don't want a custom HUD made by someone else or there's that little thing in your favourite HUD that you just hate(!) and wanna change it. Fear not! Here's a list of (hopefully) helpful links on editing your HUD: