jester, I sell Ipaqs and hp stuff for a living... the 4155 is next to the top model (after the one with a keypad on the unit witch for me would be too big for my taste h4355 i think)...
but the 4155 will let you, outta the box access internet (only through wireless network, if you dont know what it is you probably dont have one at home... but she could access internet probably at work, at a cafe, an airport, and at certain restaurants). you can use it as a MP3 player, also to display picture slide shows, watch videos, and the accessories are unlimited... you can buy a 1.3mpixel camera (through the secure digital slot) for about 130$, or for more you can buy a GPS and download a navigation program on it... could use it to map your .. ermm i mean her trips
you can also buy allmost unlimited memory incase you need some for music & pics & videos...... but appart from that she can type letters, make spreadsheets (finances) check emails (where there is wireless access to internet), go on CF

use it as a calculator, address book, agenda.... gaming.... its basicly a computer.....
if you'd like to spend a few more bucks... i'd go with the h5555... has all that this one has but more... finger print access (if she has confidential info on it, incase it gets stolen) and even acts as a universal remote control (im not sure about your's for this feature....i dont think it has it tho)... but you can expect to spend about 100$ more on that one.... but its definitely worth it if you can afford it... its faster too. but if you dont need internet access on it but still want the remote control.. i think the h2215 has it too... for about 50$ cheeper than the one you have now...
any other questions? :laughing