Is this receiver going to be used solely for music? Or are you looking to also use it to provide superior audio when watching television, as well? That will make a big difference. If you're aiming for music-only, then you've got a lot of really good, inexpensive options available to you. If you're looking to serve both music and television audio, then you need to be careful about not inadvertently being penny-wise and pound-foolish. The whole world of television is in the process of changing and to make decisions regarding purchasing a unit that you plan to carry forward with you into and through most of the next decade, you really will want to understand how you'll be watching television in the years to come.
If you're aiming to use this unit for television audio, I feel strongly that it is important to make the additional investment necessary to get a stereo receiver that is also an HDMI switcher, rather than just a plain stereo receiver. Even if you're still using a standard definition television, it may still be worthwhile factoring that in. (If you haven't yet upgraded to an HDTV, you may want to deliberately get a very cheap stereo system, now, fully intending to replace it just as soon as you get an HDTV.)
Also: Generally, units that have "other things" built-in (such as CD players) are inferior. A better solution would be to leave the receiver for receiving broadcasts, and amplifying sound to the speakers, and then connect other devices to the receiver to do other things that you want done. Even the most basic Blu-ray players, these days, are network-aware, and play CDs as well as BDs and DVDs. And many folks legally rip their CDs onto networked computers, converting them to MP3s, which can be directed into a receiver in myriad ways.
What to look for in a receiver?
Yes, definitely look for connectivity for your chosen mobile device (iPod, for example). If the receiver has a native connection to your chosen mobile device, rather than just a generic auxiliary port, all-the-better.
Personally, I wouldn't worry as much about Sirius (at least not for music): From within your home, you almost always have other ways of obtaining broadcast music: Cable companies often offer Urge, Music Choice, or other such services. In many cases, network-aware devices (televisions, disc players, and DVRs, typically) that can be connected to your receiver can play DRM-free MP3s stored anywhere on your home LAN. Some of these devices can directly access last.fm or Pandora.
Please keep this key point in mind: You may not be ready for any of the kind of technology uplifts I've described above. The point is that they're here, and even though they may not be on your mind now, they're almost surely going to be major considerations for you in the time-frame that most people aim for as the useful life of electronic equipment that they buy. So if you're not ready for these things now, you'll be best-advised to just go cheap right now, buying something that you won't be upset about replacing a couple of years from now.
One other point:
In general, wireless speakers are not-yet-ready-for-prime-time. They work, surely, but the quality and reliability is so far from what you get with wired speakers that, in the long-run, most people feel it is worth some significant level of compromise with regard to the running of the wires to get that superior performance. However, perhaps you're trying to project the sound outside? That might be a good use where wireless speakers would make more sense.