AAC is an ideal lossy codec and format. I can see why Apple chose to ditch MP3 and go with protected AAC format. It's modern, super efficient, it has great psychoacoustics, and it can be wrapped with lots of DRM and it easily supports tagging. When you use Linux, your options are limited though. Protected AACs are a pain in the butt to read and modify on Linux. This is why I only bought 1 song from iTunes in the past decade.
I can't tell the differences between WAV and FLAC files even on my high end setup. They sound identical to me with numerous ABX tests. However, FLAC is preferred over WAV because it gets 40% compression ratio and it supports tagging and multi-channel hi-rez music.
Really, LAME 3.9.9 --preset-insane 320 Kbps MP3 is an ideal codec and format. It's now my favorite format for 16 bits 44.1 kHz CD quality music. FLAC is for 24 bit 44.1 - 192 kHz high resolution and multi-channel music. I understand the differences and advantages of both formats quite well.
Nero 400 CBR is too niche. It's extremely difficult to find digital audio electronics that read that format outside of a PC. I'd have to use VLC which is not a music management software player to read Nero files.
MP3 is not the most efficient codec available, but it's a stalwart. It gets universal support.
I get 4.4:1 compression ratio with 320 Kbps MP3s compared to WAV files. That's amazing!
I get 9.5:1 compression ratio with MPEG-4 .M4V compared to DVD-Videos. That's even more amazing!
The thing that I like most about MP3 is that I don't need to worry about transcoding from WAV or FLAC to another format because I know MP3 will be here to stay for a long time. CDs will continue to be pressed and sold worldwide for a long time. MP3s will continue to be encoded and sold for a long time.
I don't see the point in transcoding to the latest and greatest audio codec and format of the day just because it's popular. With my large library, it just takes too much damn time even though I have a System76 Leopard Extreme:
2nd Generation Intel Core i7-3970X Extreme Edition 3.50 GHz L2 15 MB - 6 Cores with Hyperthreading
64 GB - 8 x 8 GB - Crucial Elite Quad Channel DDR3 - 1333 MHz
4 GB nVidia GeForce GTX 690 with 3072 CUDA Cores
960 GB: LSI Hardware RAID 0 - 2 x 480 GB Intel 520 Series SATA III 6 Gb/s Solid State Disk Drive
CD-RW / DVD-RW Dual Layer [two of them]
Internal SD, Memory Stick, Compact Flash Card Reader
Internal PCI Express 802.11 bgn
27" Full HD SuperThin Widescreen LED Display (1920 x 1080)
Logitech Wireless Illuminated Keyboard and Performance Mouse
3 Yr. Ltd. Warranty and 3 Yr. Technical Support
Asus 12X Blu-Ray USB 3.0 burner
LaCie 4Big Quad 10 TB USB 3.0 HDD
Western Digital My Passport 2 TB USB 3.0 Portable HDD
System76 Lemur Ultra Thin (lemu4):
Intel Core i5-3210M
Corsair Vengeance 2 X 8 [16 GB] 1,600 MHz RAM
Crucial M4 SATA-III 6 GB/s 128 GB SSD
Intel Advanced-N 6230 802.11 BGN
14.1" 1366 X 768 LED
2 USB 3.0
1 USB 2.0
SDXC memory card slot
8X DVD burner
MP3 is an amazing format. Now, my friends and family members can share my media library remotely and securely since I use Ubuntu 12.10 64 bit GNU/Linux. We can share files quickly and play them easily on PCs, HDTVs, home entertainment systems, and my high end audio rig without any worries about compatible audio or video formats.