Nobody asked how the OP intends to use the phone. If it is mostly for phone calls, messaging and playing music clearly there are better alternatives than the N900. Another aspect if you live in the US N900 can only work at 3G speeds with T-Mobile here, it is limited to GPRS/EDGE on ATT which makes loading non-mobile versions of web-sites painfully slow while on the go.

Nokia E7 is penta-band, has h/w keyboard and overall should be a better device for general mobile phone-like usage, it does suck in the camera department though. And it runs on Symbian, which can be a pro or a con depending on your point of view. One plus is that there are more polished apps for Symbian than for Maemo. Of course there are Android alternatives, but I don't want to go there.

Edit: forgot E7 has no microSD slot, oh well, iirc Symbian^3 can mount USB flash drives out of the box